Here's my not so world-changing idea (i have other ideas that I'll talk about the day of!) for a fun session at BarCamp Vancouver 2009 (see you there):

Social Ice Cream - Easy, peasy 1,2,3 :

1. pedal/ride/board to Mario's Gelato @ 88 East 1st Avenue, it's a 5 min bicycle ride away from BarCamp! 
2. Eat Ice cream ($4 including tax and up, lactose free yummy alternatives also available!) and create something related and put it on the web tag it #socialicecream
   
3. Share it with somebody at BarCamp you don't know