go to 711 and get some slurpees, then go home and put the nastest stuff you can find in them, like cat food and stuff, and who ever finishes it first wins!
6 saltines in one minute! def the best idea.
endo board contest
will it blend? (buy a happy meal from mcdonalds...hamburger, fries, drink, put it all in a blender and whoever finishes it first wins)
most number of clothesline pins clipped onto your body
best dance moves (usually gets pretty hilarious)
best impercinations of famous people
most number of pushups