diff --git a/lib/events/calendar.sx b/lib/events/calendar.sx
index cc65f7ff..b1a5fafe 100644
--- a/lib/events/calendar.sx
+++ b/lib/events/calendar.sx
@@ -140,6 +140,20 @@
 ;;   monthly :bymonthday -> (list 15 -1)       day of month (negative from end)
 (define ev-event (fn (id dtstart duration rrule capacity) {:duration duration :id id :dtstart dtstart :capacity capacity :rrule rrule}))
 
+;; Event with EXDATE/RDATE exceptions. exdate/rdate are lists of epoch-minute
+;; starts to exclude from / add to the expansion (RFC 5545 VEVENT properties).
+(define
+  ev-event-full
+  (fn
+    (id dtstart duration rrule capacity exdate rdate)
+    {:duration duration
+      :id id
+      :dtstart dtstart
+      :capacity capacity
+      :rrule rrule
+      :exdate exdate
+      :rdate rdate}))
+
 (define ev-occ (fn (id start dur) {:id id :start start :end (+ start dur)}))
 
 ;; ---- DAILY expansion ----
@@ -360,9 +374,10 @@
                   n2)))))))))
 
 ;; ---- top-level expansion ----
+;; Raw expansion (RRULE / single event), before EXDATE/RDATE are applied.
 ;; Returns a list of occurrence dicts {:id :start :end} within the window.
 (define
-  ev-expand
+  ev-expand-base
   (fn
     (event win-start win-end)
     (let
@@ -431,9 +446,75 @@
                     win-end
                     acc
                     0)))
-              (else (error (str "ev-expand: unsupported freq: " freq))))
+              (else (error (str "ev-expand-base: unsupported freq: " freq))))
             acc))))))
 
+;; ---- EXDATE / RDATE (RFC 5545 exceptions) ----
+;; Applied AFTER raw expansion: RDATE adds explicit occurrences within the
+;; window, EXDATE removes occurrences whose start matches (EXDATE wins over
+;; RDATE). Both are VEVENT-level: (get event :exdate) / (get event :rdate) are
+;; lists of epoch-minute starts; nil for plain events.
+
+(define
+  ev-num-member?
+  (fn
+    (n xs)
+    (cond
+      ((empty? xs) false)
+      ((= n (first xs)) true)
+      (else (ev-num-member? n (rest xs))))))
+
+;; Drop duplicate-start occurrences from a start-sorted list (keep one).
+(define
+  ev-dedupe-by-start
+  (fn
+    (occs)
+    (cond
+      ((empty? occs) occs)
+      ((empty? (rest occs)) occs)
+      ((= (get (first occs) :start) (get (first (rest occs)) :start))
+        (ev-dedupe-by-start (rest occs)))
+      (else (cons (first occs) (ev-dedupe-by-start (rest occs)))))))
+
+(define
+  ev-apply-exceptions
+  (fn
+    (event base win-start win-end)
+    (let
+      ((id (get event :id))
+        (duration (get event :duration))
+        (exdate (ev-or (get event :exdate) (list)))
+        (rdate (ev-or (get event :rdate) (list))))
+      (let
+        ((rdate-occs
+           (reduce
+             (fn
+               (acc d)
+               (if
+                 (and (>= d win-start) (<= d win-end))
+                 (cons (ev-occ id d duration) acc)
+                 acc))
+             (list)
+             rdate)))
+        (let
+          ((no-ex
+             (filter
+               (fn (o) (not (ev-num-member? (get o :start) exdate)))
+               (append base rdate-occs))))
+          (ev-dedupe-by-start (ev-sort-occs no-ex)))))))
+
+;; Expand an event into occurrence dicts within the window, applying any
+;; EXDATE/RDATE exceptions. This is the public entry point.
+(define
+  ev-expand
+  (fn
+    (event win-start win-end)
+    (ev-apply-exceptions
+      event
+      (ev-expand-base event win-start win-end)
+      win-start
+      win-end)))
+
 ;; ---- multi-event expansion (sorted by start) ----
 
 ;; Insertion of one occurrence into a start-ascending list.
diff --git a/lib/events/scoreboard.json b/lib/events/scoreboard.json
index 5c0a02e1..01d99c32 100644
--- a/lib/events/scoreboard.json
+++ b/lib/events/scoreboard.json
@@ -1,10 +1,10 @@
 {
   "lang": "events",
-  "total_passed": 240,
+  "total_passed": 248,
   "total_failed": 0,
-  "total": 240,
+  "total": 248,
   "suites": [
-    {"name":"calendar","passed":37,"failed":0,"total":37},
+    {"name":"calendar","passed":45,"failed":0,"total":45},
     {"name":"availability","passed":22,"failed":0,"total":22},
     {"name":"api","passed":24,"failed":0,"total":24},
     {"name":"booking","passed":82,"failed":0,"total":82},
@@ -13,5 +13,5 @@
     {"name":"reminders","passed":14,"failed":0,"total":14},
     {"name":"federation","passed":23,"failed":0,"total":23}
   ],
-  "generated": "2026-06-07T05:59:03+00:00"
+  "generated": "2026-06-07T06:25:58+00:00"
 }
diff --git a/lib/events/scoreboard.md b/lib/events/scoreboard.md
index 3e85f60c..c1517e72 100644
--- a/lib/events/scoreboard.md
+++ b/lib/events/scoreboard.md
@@ -1,10 +1,10 @@
 # events scoreboard
 
-**240 / 240 passing** (0 failure(s)).
+**248 / 248 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
-| calendar | 37 | 37 | ok |
+| calendar | 45 | 45 | ok |
 | availability | 22 | 22 | ok |
 | api | 24 | 24 | ok |
 | booking | 82 | 82 | ok |
diff --git a/lib/events/tests/calendar.sx b/lib/events/tests/calendar.sx
index e679398e..a65980c4 100644
--- a/lib/events/tests/calendar.sx
+++ b/lib/events/tests/calendar.sx
@@ -421,6 +421,115 @@
             (list (quote a) (list 2026 6 2))
             (list (quote a) (list 2026 6 3))))))))
 
+;; ---- EXDATE / RDATE exceptions ----
+(define
+  ev-cal-ex-run-all!
+  (fn
+    ()
+    (do
+      ;; EXDATE removes a matching occurrence from the recurrence
+      (let
+        ((ex
+           (ev-event-full
+             (quote standup)
+             (ev-dt 2026 6 1 9 0)
+             30
+             {:freq :daily :count 5}
+             1
+             (list (ev-dt 2026 6 3 9 0))
+             (list))))
+        (ev-cal-check!
+          "EXDATE excludes the matching occurrence"
+          (ev-cal-starts (ev-expand ex (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          (list (list 2026 6 1) (list 2026 6 2) (list 2026 6 4) (list 2026 6 5))))
+      ;; EXDATE that matches nothing is a no-op
+      (let
+        ((ex2
+           (ev-event-full
+             (quote s)
+             (ev-dt 2026 6 1 9 0)
+             30
+             {:freq :daily :count 3}
+             1
+             (list (ev-dt 2026 6 9 9 0))
+             (list))))
+        (ev-cal-check!
+          "EXDATE not matching any occurrence is a no-op"
+          (len (ev-expand ex2 (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          3))
+      ;; RDATE adds an explicit occurrence (within the window)
+      (let
+        ((rd
+           (ev-event-full
+             (quote s)
+             (ev-dt 2026 6 1 9 0)
+             30
+             {:freq :daily :count 3}
+             1
+             (list)
+             (list (ev-dt 2026 6 10 9 0)))))
+        (do
+          (ev-cal-check!
+            "RDATE adds an explicit occurrence, sorted in"
+            (ev-cal-starts (ev-expand rd (ev-date 2026 6 1) (ev-date 2026 7 1)))
+            (list (list 2026 6 1) (list 2026 6 2) (list 2026 6 3) (list 2026 6 10)))
+          (ev-cal-check!
+            "RDATE outside the window is dropped"
+            (len (ev-expand rd (ev-date 2026 6 1) (ev-date 2026 6 5)))
+            3)))
+      ;; RDATE coinciding with an rrule occurrence is de-duplicated
+      (let
+        ((rdup
+           (ev-event-full
+             (quote s)
+             (ev-dt 2026 6 1 9 0)
+             30
+             {:freq :daily :count 3}
+             1
+             (list)
+             (list (ev-dt 2026 6 2 9 0)))))
+        (ev-cal-check!
+          "RDATE duplicating an occurrence does not double it"
+          (len (ev-expand rdup (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          3))
+      ;; EXDATE wins over RDATE for the same datetime
+      (let
+        ((both
+           (ev-event-full
+             (quote s)
+             (ev-dt 2026 6 1 9 0)
+             30
+             {:freq :daily :count 3}
+             1
+             (list (ev-dt 2026 6 2 9 0))
+             (list (ev-dt 2026 6 2 9 0)))))
+        (ev-cal-check!
+          "EXDATE wins over RDATE and the rrule for the same date"
+          (ev-cal-starts (ev-expand both (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          (list (list 2026 6 1) (list 2026 6 3))))
+      ;; RDATE-only event (no rrule)
+      (let
+        ((ronly
+           (ev-event-full
+             (quote s)
+             (ev-dt 2026 6 1 9 0)
+             30
+             nil
+             1
+             (list)
+             (list (ev-dt 2026 6 5 9 0) (ev-dt 2026 6 3 9 0)))))
+        (ev-cal-check!
+          "RDATE-only event yields dtstart plus the extra dates, sorted"
+          (ev-cal-starts (ev-expand ronly (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          (list (list 2026 6 1) (list 2026 6 3) (list 2026 6 5))))
+      ;; plain ev-event (no exception keys) is unaffected
+      (let
+        ((plain (ev-event (quote p) (ev-dt 2026 6 1 9 0) 30 {:freq :daily :count 3} 1)))
+        (ev-cal-check!
+          "plain event without exceptions expands unchanged"
+          (len (ev-expand plain (ev-date 2026 6 1) (ev-date 2026 7 1)))
+          3)))))
+
 (define
   ev-calendar-tests-run!
   (fn
@@ -430,4 +539,5 @@
       (set! ev-cal-fail 0)
       (set! ev-cal-failures (list))
       (ev-cal-run-all!)
+      (ev-cal-ex-run-all!)
       {:failures ev-cal-failures :total (+ ev-cal-pass ev-cal-fail) :passed ev-cal-pass :failed ev-cal-fail})))
diff --git a/plans/events-on-sx.md b/plans/events-on-sx.md
index 1bdf8742..23257384 100644
--- a/plans/events-on-sx.md
+++ b/plans/events-on-sx.md
@@ -18,7 +18,7 @@ capacity rules, transactional booking, and a flow-driven notification dispatcher
 
 ## Status (rolling)
 
-`bash lib/events/conformance.sh` → **240/240** (Phases 1-4 + ext: federated free/busy, waitlist)
+`bash lib/events/conformance.sh` → **248/248** (Phases 1-4 + ext: fed free/busy, waitlist, EXDATE/RDATE)
 
 ## Ground rules
 
@@ -86,6 +86,13 @@ lib/events/api.sx ── (events/schedule) (events/book) (events/agenda) ──
 
 ## Progress log
 
+- 2026-06-07 — RRULE exceptions EXDATE/RDATE (extension). `ev-event-full`
+  carries :exdate/:rdate (epoch-minute starts). Raw expansion renamed
+  `ev-expand-base`; `ev-expand` now applies exceptions: RDATE adds explicit
+  in-window occurrences, EXDATE removes matching starts, duplicates de-duped,
+  EXDATE wins over RDATE and the rrule (RFC 5545). RDATE-only events (no rrule)
+  supported. Plain `ev-event` (no exception keys) unaffected. +8 tests,
+  248/248 green.
 - 2026-06-07 — Waitlist + auto-promotion (extension). When an occurrence is
   full, `ev/waitlist!` queues actors FIFO (:waitlist/:unwaitlist events on the
   same stream; waiting fold is independent of the seat fold since taking a seat