Tip by Jean Hagler, from Savage, MT.
A fun serving drill is called Serving Bunco (after the dice game popular in our area - pronounced "bonko" - don't ask me why)
Two teams are scrimmaging - live ball. If the server, serves an ace - they wear the Bunco hat (you can use any hat you like) until another server gets an ace - then they get to wear the hat and so on. This continues as long as you set the game - first to 25 etc. At the end of the game, the player wearing the hat gets to decide what the others' punishment is.
I promise they get super competitive about keeping the hat. :)