Are the kids spending time in lines at the events? You might want to work out a lesson plan with a circuit ahead of time. It's harder if you don't have many bars, for example, but you can still use other things, i.e. block, floor bar, etc.
A typical L2 bar circuit for me would be like - focus: back hip circle
-start with jump ups, try to keep straight arms...surprisingly hard. do 10
-move to other bar, 10 tuck ups (easy leg lifts on low bar)
-move to third station, maybe strength (sit ups, cast position with feet elevated) or p-bars at two different heights (hands on higher, feet/knees on lower) 10 modified pull ups
-another station, if you have another bar, do glide swings or some exercise like that, or use a mat for push ups, sit ups, dips, hollow, whatever you haven't done.
Then the first bar changes each time they come around. ten jump ups - pullover, five casts, roll down - pullover, three casts, back hip circle - add glide swing then BHC - maybe finish with hollow hang (toes up, bar at hips)