A lump of butter wrapped in clingfilm. It exploded brilliantly when chucked at a blackboard.
One of my students threw one of his crutches at another disabled man,then the fight was on!
A cat my girlfriend had the one day it came running in to I livingroom and jumped on my lap it was so funny
A toy baby that malfunctioned and the babies head blew up
A coat rack. Don't ask.