1. Take a Sharpie to a plain white tee and you get a 404 Error.
2. Affix clothing and dryer sheets to yourself to personify static cling.
3. A plaid shirt and rugged stubble can help you identify as a Brawny man.
4. Buddy up with a thinner doppelganger and go as a before-and-after weight loss ad.
5. Ping-Pong balls and a baggy sweater can instantly transform your child into a hideous* monster.
6. A light blue placard against a navy background makes a Photoshop costume for the lazy.
7. Stick black dots on a red outfit and you, my friend, are now a ladybug.
8. Add a fanny pack to literally any outfit you already have and you're instantly a tourist.
9. Show of your dual appreciation for wordplay and slapstick with this pun.
10. All it takes to be bouncers are black suits, sunglasses, and a rope running between you.
11. Another great play on words: ceiling fan.
12. Don a fake ponytail and wear an unbuttoned flannel shirt — you're Billy Ray Cyrus (which is so much more subversive than Miley).
13. Channel Jane Goodall in head-to-toe khaki and a stuffed chimpanzee.
14. Wednesday Addams made easy with a black button-down tucked into a black skirt. Add braids and make use of your bitchy resting face.
15. Don an oversize suit jacket and menswear-inspired pants for a look worthy of Elaine Benes.
16. Take your basic cat costume one step further with a nod to a musical legend.
17. Let everyone know you'd rather be at home with a "night in" costume.
18. You don't need a hazmat suit to be Walter White.
19. An extra-large shirt and a frenemy make a costume moms everywhere will love.
20. A little construction paper and elementary drawing skills go a long way in an Operation costume.
21. Household products and numbered sweaters make an easy Supermarket Sweep costume.
22. A black top, white bottoms, backward cap, bandana, and a bouquet make you a Banksy piece.
23. Put that vintage leather jacket you're too nervous to wear to good use and release your inner Fonz.
24. Wear a nondescript outfit and carry a puppet. You're a puppeteer now.
25. All you need is a sign to be an out-of-work nudist.
26. A Snuggie and a football helmet turns you into Fantasy Football.
27. A tank top with boob-circle cutouts turns you into Regina George.
28. Become a human stick figure with a monochromatic outfit and a contrasting tape color.
29. If you really have nothing to wear, strip (nearly) bare and go as an underwear model.
30. And if all else fails, just go as the timeless Halloween classic: sexy sheet ghost.
UPDATE
The Bill Cosby costume, formerly item #5 of this list, has been removed in light of recent publicized sexual assault and rape allegations against Cosby.