How about some event ideas for a Fun Fly event?
1 - If you don't have partners, you could try the balloon course hauckf suggests, but having the pilot look at his plane in a mirror held by the judge. We used a large mirror like you would have on the back of your bathroom or bedroom door.
2 - Slow flight, set up two points on the runway, see how slow you can fly between these points. Have a person at each point, the first starts a stopwatch when plane passes him, then stops it when the other signals him the plane has past his point.
3 - Takeoff, do three loops, three rolls, three more loops and land. You are timed from takeoff to touchdown. If you have partners, do a relay, second plane takes off when first touches down. Time from first takeoff to last touchdown.