The announcement at Relief says:
Submisisons for Coach's Midnight Diner will remain open until May 31st. After receiving some harried emails from folks we met at Calvin ("I just found out about the Diner! My story is almost finished but not quite! Can I please have more time?!?!?") I decided to go ahead and leave it open. So go ahead and finish your Shatner on a Plane story and get it in!