Play hide and seek in the mall.

Walk into an elevator full of strangers and say, "You're probably all wondering why I've gathered you here today."

Eat vanilla pudding from a mayo jar in heavily populated places.

Order a pizza for delivery, walk to the pizza place, and get a free ride home from the pizza delivery guy.

Dress like Spiderman and climb a building.

Glue coins to the sidewalk and videotape it for extended laughs.

Go cone-ing through a drive thru and grab those cones by the ice cream.

Hire two private detectives and have them tail each other. Then watch the chaos.

Speak with an accent for an entire day. If your friends ask you why you've suddenly developed an accent, convince them that you've always had an accent and they're horrible friends for never noticing.

Draw eyebrows on your dog--or even better--borrow a friend's dog!

Make a sign that makes no sense and go to a rally or protest.

Invite some friends over and do the most hideous makeup job possible, then go shopping like that's your everyday look.

Follow joggers around in a car, and blast Eye of the Tiger for encouragement.

Wear a LIFE shirt and hand out lemons.

Walk up to strangers and act like they are old acquaintances.

Stalk around the mall and loudly hum the Mission Impossible theme.

Tape clear saran wrap around your friend's doorway. See if they fall for the prank and walk into the saran wrap, or notice and become confused by its presence.

Go snorkeling in a public fountain.

Use a fake name at Starbucks. Mike Hunt works well...

Write down deep, philosophical questions on toilet paper rolls in public restrooms.

Run into a store and ask what year it is. When someone answers, yell, "It worked! It worked!" and run out cheering.

Pretend to be a Wal-Mart greeter, and greet everyone with awkward hugs.

Go to any store that sells wrapping paper and challenge other customers to a duel with the gift-wrap tubes.