Get boxes of condoms and randomly put them in people's carts when they don't realize it.

Run up to an employee (preferably male) while squeezing your legs together and yell at him "WHERE ARE YOUR TAMPONS?"

Walk up to an employee and tell him in your most official tone, "I think we've got a Code 3 in housewares", and see what happens.

Put M&M's on layaway.

Move "Caution: Wet Floor" signs to carpeted areas.

Set up a tent in the camping department, tell others you'll invite them if they bring pillows from Bed and Bath.

When someone asks you if you need help, begin to cry and say "Why won't you people just leave me alone?"