Aww, congrats.
They can have a small stick or something similar to hop on. They figure that out within days.
Ofcourse, there's the fun game of 'kick shavings in the waterbowl, right after it's been changed' which is a variant on 'poop in the water'. Another favorite is 'flip the plate over', that one stays fun, even as older birds. You just take a small plate, bowl or lid and put some treats on it, and they will flip it for you, after they have walked through it and pooped on it ;-)
The most fun they have is with eachother. And eating (mine enjoyed small bits of yogurt at one week old, cooked oats and weeds at two weeks, can't give them that stuff until they're big enough to have some grit)