I have found through one of our club members that macaroni works better
than rice
 
My kids got tired of the rice but the macaroni is played in almost every
day, I put a little plastic ball with a bell inside (not one of the kind
with hole) and usually when one or more climb inside they will play with
the ball while snorkeling around in the macaroni
 
Patrick and the crew
[Posted in FML issue 5207]