Summer Camp

Hi - I am new to this board and I would like help on brain storming some camp "pranks".
I will be the camp nurse for our church's summer camp (1 week) for 4-8th grade (boys and girls).

I would really like to play some edifying "pranks" on them - each cabin etc.

Some ideas I have come up with for examples are:
-hiding alarm clocks set to go off in the early morning (2am) with a note that says "Early in the morning I will rise to praise Thee"

or -filling up a small kiddie (inflatable) pool in the middle of the cabin with toy fishing gear with a note that says "I will make you fisher of men"

Any ideas? Thanks!