At school, a staple of classroom mischief was a game called 'bollocks!" where the aim was to shout "bollocks!" at increasingly loud volumes each participant going one up on the previous person. I can't remember there being any winners or losers, it was played until someone was the first to back down. Or the teacher told us off.

For group, or solo.

Play a sound. the next sound must be louder than the last, until it is judged that it can get no louder.

Aim for as many incremental steps as possible.

Variation: As above but starting loud and getting quieter and quieter.

May 2009