1. Take shopping carts for the express purpose of filling them
and stranding them at strategic locations.
2. Ride those little electronic cars at the front of the store.
3. Set all the alarm clocks to go off at ten-minute intervals
throughout the day.
4. Don't bother doing your own shopping.  Simply find someone with a full trolley containing roughly the items you need, and when they are not looking take it and go pay for it at the checkout. (this is not stealing, they did not own the items yet, they were simply 'moving them around')
5. Contaminate the entire auto department by sampling all the
spray air fresheners.
6. Challenge other customers to duels with tubes of gift-wrap.
7. Leave cryptic messages on the typewriters.
6. Re-dress the mannequins as you see fit, then arrange them into erotic poses. (be creative with the gift-wrap tubes used in point 6).
9. When there are people behind you, walk really slowly,
especially in thin aisles.
10. Walk up to an employee and tell him in an official tone, "I
think we've got a code 3 in housewares," and see what happens.
11. Turn all the radios to polka stations; then turn them off
and turn the volume up to full blast.
12. Re-enact a fatal incident involving the automatic doors.
13. Walk up to complete strangers and say, "Hi. I haven't seen
you in so long." etc. See if they play along.  Insist on calling them 'Bob', and if they protest, get angry about it (violent if necissary).
14. While walking through the clothing department, ask yourself
loud enough for all to hear, "Who buys this crap anyway?!"
15. When you leave the store, try your car keys in the door of every car in the car park until you get to your own.  Then drive off as if this is perfectly normal. (Note- if you don't actually own a car and walked to the store, attempt the above by substituting car keys with your house keys).
16. Ride a display bicycle through the store; claim you are
taking it for a test drive.
17. Follow people through the aisles, staying about 5 feet
behind them. Do this until they leave the store.
18. Ask if you can test some super-glue before buying it, then walk around the store gluing random items to other items/customers/staff.  For added fun: See how many cashiers you can glue to each-other before any of them notice.
19. As the cashier runs your purchase over the scanner say "BEEP" in a loud voice.  Repeat this for every item, and for other customers items.  If the cashier protests, kill them.

20. Take off your shoes and tell them you want to return it and
when they say you didn't buy it there say "The customer is always right dammit!!"  Make a scene.
21. Move "Caution : Wet Floor" signs to carpeted areas.
22. Set up a tent in the camping department; tell others you
will only invite them in if they bring pillows from Bed and Bath.
23. Test the fishing rods and see what you can catch from other
aisles.
24. Ask other customers if they have any Grey Poupon.
25. Drape a blanket around your shoulders and run around saying,
"I'm Batman. Come Robin, to the Batcave."
26. Climb things.
27. Randomly throw things over into neighboring aisles.
28. Play with the calculators so that they all spell "hello"
upside down. Once you have mastered this, progress to "boobs".
29. When someone asks you if you need help, begin to cry and
say, "Why won't you people just leave me alone?"
30. When 2 or 3 people are walking ahead of you, run between
them yelling "Red Rover."
31. Make up nonsense products and ask employees if there are any
in stock. (i.e.: Shnerples).  Do a vague hand-mime of what a 'Shnerple' looks like to assist them.
32. Take up an entire aisle in toys by setting up a full-scale
battle with G.I. Joe vs. X-men.
33. Take bets on the battle from above.
34. Test the brushes and combs in Cosmetics on all the live animals in Pet-Care.
35. While handling knives in the kitchen department, suddenly ask
the clerk where the anti-depressants are. Act as spastic as
possible.
36. Hold indoor shopping cart races.
37. Dart around suspiciously while humming the theme from
Mission Impossible.
38. Attempt to fit into very large gym bags.
39. Attempt to fit others into very large gym bags against their will.
40. Say things like, "Would you be so kind as to direct me to
your Twinkies."
41. Set up a "Valet Parking" sign in front of the store.
42. Two words: Marco Polo.
43. Leave Cheerios in lawn and garden, pillows in the pet
section, etc.
44. "Re-alphabetize" the CD's using an alternative alphabet of your choosing.
45. In the auto department, practice your Madonna look with
various funnels.
46. When someone steps away from his or her cart to look at
something, quickly place random combinations of items in their cart, such as 'A Large Cucumber and a Tub of Vasceline'.
47. Relax in the patio furniture drinking beer until you get kicked out.
48. When an announcement comes over the loudspeaker, drop to
your knees and scream, "No, no, its those voices again."
49. Pay off layaways 50 cents at a time.
50. Drag a lounge chair over to the magazines and relax. Go to
the food court, buy a drink, and explain that you don't get out
much and ask if they can put a little umbrella in it