Problem: I've agreed to host a prank on our DM this Friday evening, in honor of his 40th birthday (which happens on Saturday). He'll sit down behind his DM screens and whatnot, only to have the assembled players stand up, rotate chairs, and I'm the DM for the evening, running a one-time event with something cool or funny or interesting that keeps everyone entertained. Difficulty: I haven't DM'd in years. I can fake it as a player, but people expect you to know your shit if you're going to DM. Options: I could run a quick adventure that I noticed over on Metafilter. It has the advantage of being short and funny. Only problem there is that the stats don't necessarily align with any system I've ever played, and the last time I rolled up characters was for an AD&D 2nd Edition campaign, circa 1980-something. I could create something out of whole cloth. Everything I've thought of in the last 24 hours, however, has been the start of something epic, and I'm worried that it won't be satisfying to a 4-hour gaming session crowd. No closure. What say you, Obi-Wannabies. You're my only hope.