Update root challenges and placeholders for May 20th Meetup

wiki-content-gitea/Important-Dates.md

@@ -6,14 +6,14 @@
 
 ### Next Meetup
 
-- **March Meetup: March 18th, 2026**
-  - Challenge announcement for March 2026 Challenge ("Bring an Experiment")
-  - Judging of February 2026 Challenge ("Bring Your Best")
-
 - **April Meetup: April 29th, 2026**
-  - Special Topic and activities TBD
+  - Challenge announcement for April 2026 Challenge ("Bring an Experiment (Round 2!)")
   - Judging of March 2026 Challenge ("Bring an Experiment")
 
+- **May Meetup: May 20th, 2026**
+  - Special Topic and activities TBD
+  - Judging of April 2026 Challenge ("Bring an Experiment (Round 2!)")
+
 ## Regular Meeting Schedule
 
 ### Standard Schedule
@@ -44,6 +44,14 @@ See [Current Challenge](Current-Challenge) for complete details.
 - **Submission Deadline**: April 29, 2026
 - **Judging**: April 29, 2026 meetup
 
+See [Current Challenge](Current-Challenge) for complete details.
+
+### April 2026: "Bring an Experiment (Round 2!)"
+
+- **Challenge Announcement**: April 29, 2026
+- **Submission Deadline**: May 20, 2026
+- **Judging**: May 20, 2026 meetup
+
 See [Upcoming Challenge](Upcoming-Challenge) for updates.
 
 ## Meeting Locations
@@ -57,4 +65,4 @@ Fargo, ND 58102
 
 ---
 
-*Last updated: April 14, 2026*
+*Last updated: April 30, 2026*