For fun fly challenges at the field....
- Timed Flight (2 minutes from takeoff to landing - either no timers allowed for anyone, or a caller hollers out at 30 second intervals)
- Bomb Drop (rubber band attach a flat popsicle stick with a nail sticking up to the top of the wing. Slide a washer with a streamer tied to it over the nail. When the plane rolls over, or even does a sharp quick dive, the washer and streamer will come off. Closest to the target wins.
- Spot Landing (stick a ballon on the field, closest touchdown wins)
- Loop and Rolls (quickest time to takeoff, perform 3 loops and 3 rolls and land)
- Lots of Loops (from level flight, 1 minute timer for as many loops as possible)
- Taxi Races (pin several balloons in the field to make a ground race course - quickest time around the course 1 time without taking off wins)
- Formation Flying (for the very brave - two circuits of the pattern maintaining a formation position - behind right or behind left)
There is also a good Model Aviation link with some ideas - I like the "dice loops"
https://www.modelairplanenews.com/10-great-fun-fly-events-and-ideas/