Firstly, a friend of mine was “doing group” last year, and didn’t have a story, and he made one up (Right/wrong… not for now). One of the brats in his group butted in and told him “you said it wrong” in the middle. Hilarious.
There is a game called “Eidim Zomemim” (even though technically the name is wrong) where two guys go out and make up a story of some crime. Then they have to come in seperately and they get cross examined. If they are caught contradicting, then they lose the point.
(After two weeks playing this, they will come up with strategies, such as “Say “no” to any yes/no question” beforehand… gets more interesting weekly)