1. Walk up to them and ask them for their autographs.
2. Walk up to them, introduce yourself extremely upbeat and friendly-like and end the conversation by saying "It was nice to meet you. It's so cool to talk to people outside of the asylum." Then walk away.
3. While walking down the street, in a mall or any other such place, laugh out loud for no apparent reason. Be as creative with the way you laugh as you wish.
4. Run up to them, excitedly calling them Father, Mother, Aunt or Uncle. If you dare, hug them.
5. While passing a random stranger, stop and exclaim to them, "You have no idea!" in a mixture of anger and sadness.
6. Follow a stranger around. If they notice, take a random small object like a brick or a bar of chocolate and hold it up to your ear, pretending to be busy conversing on it.
7. Skip. Don't walk.
8. Walk up to them and ask them if they are some celebrity that looks nothing like them. Opposite gender, if you dare. Examples: Old man - Justin Bieber, middle aged woman - Chuck Norris, young adult man - Batman.
9. Call random numbers while passing strangers.
10. If somebody asks you for directions, look them right in the eye, try to stare them down, then walk away.
11. Burst into a short fit of dance every once in a while.
12. Ask a stranger a trivial question, like the time of day. When they answer, suddenly make your expression extremely serious and sober and say. "I see. Look... I was never here, got it?" If you have any small cash on you you'd be willing to give up like a dollar or a quarter, give it to them.
13. Introduce yourself to strangers. Then say "Just please don't tell Big Brother."
14. Punch yourself in the face randomly. But make sure someone notices it, cause it would be a shame to let it go to waste.
15. If you're under 18, sing "Too sexy for my wife, too sexy for my kids, too sexy for my mother-in-law..."
16. If you're 13 or over, mutter "I don't get it, I don't WANNA go to kindergarden!" But mutter it loudly enough for someone to hear you.
17. Randomly shout out "You people are all crazy!"
18. Introduce yourself to strangers like this: "Hi, I'm {insert your name here}, I'm {insert your age here} years old, I'm married, twice (your age doesn't matter) and my best friends are some funny people in white coats who call me "clinically insane." Do you think I'm cute?"
19. Spray the floor/ground with disinfectant.
20. Giggle, suddenly become very sober, repeat.
21. Brush your teeth, shave or both in a public place.
22. Take out a lolipop and start sucking it. When a stranger walks by, offer it to them.
23. If a stranger asks you something (e.g. directions, the time of day), answer it by saying "That's what you think" or "You don't need to know."
24. Tap a stranger on the back as if you want to ask them something. When they turn around, say "Quark," then walk away.
25. Tap a stranger on the back as if you want to ask them something. When they turn around, run away giggling.
26. In a public place like a mall, take out a skipping rope and start skipping.
27. Run/walk up to a stranger and exclaim "Look! Behind you!" When they turn around and see nothing, say "Never mind."
28. Walk up to a stranger and preach a parable to them.
29. Have a blank rectangle of paper on hand. Walk up to a stranger and give it to them, saying it's "my card."
30. If a stranger wants to ask you a question, exclaim "Excuse me, I'm on the phone." Unless you actually ARE on the phone when they ask you, in which case tell the person on the other line angrily, "Excuse me, stop being so rude! Can't you see someone's trying to ask me a question over here?!" Then hang up (or pretend to) and tell the stranger "I'm sorry, you know how insensitive people can be. So, what did you want to ask me?" They had it coming, anyway.
31. Walk up to a stranger and tell them in a debative tone, "I disagree. I'm a die-hard Sonic the hedgehog fan."
32. Wait for the elevator to come without pressing the button.
33. Wear a business suit, briefcase and sunglasses somewhere regular.
34. When a stranger passes you, stand at attention and salute them.
35. Wear a hand puppet everywhere you go.
36. Show disgust and spit on the floor. Then, act totally surprised and try to clean it up with a handkerchief.
37. Just stand around, looking confused and lost. If someone comes up to you and asks if you're lost or something, politely answer "No, thank you, I had a big breakfast. But thanks for asking!" Bonus points if you mention "big breakfast" late in the afternoon.
38. Take out a piece of paper and write "The cake is a lie" on it. Then pass it off to a stranger any way you can, perhaps with the #29 method.
39. If you have a pizza in a box that clearly states it's from Pizza Hut, Mario's, etc, or just the empty box, walk around with it declaring "Home-made pizza for sale!"