Pick and Remix
The leader picks a chant everyone knows. For example, 'Beep Beep' or 'I've got a hunk of tin', and everyone sings it. At some point, the leader shouts 'Re-mix!...x style', and the person x choses a new way of chanting. Examples would be pirate style, upper class, like a rap-artist, operatic, et cetera. It can be played especially well at meal times, or as a filler while waiting around.