Urinal cakes
Have no effect, apart from a slight cleaning product smell (only on the day they're put in). The actual purpose is to give men something to aim at, in the hope that they will point it vaguely toward the urinal instead of pissing all over the floor for pointless amusement.

A better idea came from the Netherlands (don't they all?!) where at Schipol airport, the urinals have little black flies painted beneath the glaze. Apparently the slight distraction of having a target to aim at reduced pissy floor moppage by XX? litres per day....
(Greencloud Wanted to go fishing on, Mon 5 Nov 2007, 14:48, Reply)