here are a few ideas for the BBQ bike games:
1. As Fred posted earlier, the old favorite is the Slow Race, line up about 4 or 5 riders side by side and see who can go the slowest in a marked distance (around 50ft.) without putting your feet down.
requires great balance
2. Board Race, place a half dozen 2x4x8s on the ground end to end like this,------,start a rider on one end and see how far they can ride ON the boards without driving off. requires driving in a very straight line, it's tough and fun.
3. Round and Round, tie about a 30ft. rope to a fixed object, like a chair, pole, cooler, and have the rider hold the other end of the streched out rope with their left hand,(you need the right hand for throttle control) start going around in circles until the rope winds up to the center. (kinda like a May Pole) see who can get closest to the center. You can't put the left hand on the handlebar. It's harder than it sounds.
4. Moped Tire Toss, it's what it is, see who can toss a tire (off the rim,duh) the farthest. fun for guys and gals. The best way is to spin around in circles before releasing, like a shot put.
Hope you have a big field or park to do these things.
These games are for solo riders, I have more for couples, but most peds are single riders. We play these games at our Harley events and have a ball, oh,by the way, I forgot Biker Ball, that's when you push a beer keg or a trash can with the front wheel across a measured distance, usually 3 or 4 riders at the same time, resulting in a few collisions. Have fun in KZoo everybody.