Whoopee cushions are tame. When we want to humiliate a co-worker, we slip a RAP4 Pressure-Activated Landmine from Real Action Paintball under their desk. The device is charged with a C0 2 cartridge, and when someone steps (or sits) on the thing, it releases a cloud of paint. You can fill it with any liquid or powder — we recommend Wite-Out or nondairy creamer.