15 Things You Won't Believe You Can Do with $21

End the "I don't know...what do you want to do?" game with these affordable, get-out-of-a-rut ideas. There's a pick for just about every personality, which might make you enjoy parting with your pals Andrew Jackson and George Washington.

9. Play Activity Roulette

Choose an event on Groupon or LivingSocial to try at random—preferably one you'd never otherwise consider. Recent examples from the sites: a cupcake tour ($20), bike rentals at a local park ($10), Brazilian waxes ($17)—even a Halloween jack-o'-lantern tour featuring 5,000 carved pumpkins ($10/person).

10. Take Care of Yourself the Day Before an "I Can't Believe I'm Doing This" Presentation

Once you've done all the prep work, head to the mall—but not for the reason you might think. Bypass the shops and invest $3 in one of those 15-minute, vibrating massage chairs (yup, like the one your Grandpa uses—they're surprisingly relaxing). When you're done, visit a nail salon and request a polish change instead of a manicure. It doesn't have all the bells and whistles of a traditional mani, but it only costs about $6 to $8 before tip. One final touch: Visit the makeup counter to sample your favorite perfumes. Research shows that women tend to feel more confident after spritzing their favorite scent. Some stores sell travel-size fragrances or body sprays at a fraction of the full-size price.

11. Eat Around the World

Food trucks aren't just lunchtime staples in LA, NY and Miami anymore. They're popping up all over the U.S.; and with them, comes food-truck festivals. Instead of chasing one truck all day, you can try dumplings, lobster rolls, Korean-Mexican fusion BBQ, or red-velvet ice cream sandwiches, all for about $2 to $12 per dish. It's an eclectic-yet-delicious blend of flavors you won't find on most restaurant menus.

12. Knock an Always-Wanted-to-Try-That Hobby Off Your Bucket List

Knitting, designing handbags, crafting flowers out of gum paste—whatever your DIY interest, there's a good chance Jo-Ann Fabric and Craft Stores, Craftsy or Michaels has a course for it. All three regularly offer discounts that bring pricier courses—like cake decorating—down to $20.

13. Root for the Lesser-Known Home Team

There's no faster way to feel part of a community than to don your local university's colors and head to a sports game. (Seriously—just count the high-fives and random conversations that arise when you're heading to your seat.) Many college football teams offer tickets as low as $10; and, in some cases, admission to other sports, like volleyball or softball, can be free, says Buscemi. That leaves you with just enough money to pick up a hot dog and soda at the stadium.

14. Turn Your Dining Room into the Ultimate Game Show Where You Can Really Get to Know Your Friends (Ryan Seacrest not included)

First up, a battle of the minds: Heads Up! is a $1 app that takes charades to a ridiculous new level (and yes, it involves holding your smartphone up to your forehead, so the guessers look just as ridiculous as the actors). Next, a battle of brawn, sort of: a $14 desktop ping-pong kit transforms your dining room table into a table tennis court. You may want to hide the fine china. Leftover cash can go toward a crowd-pleasing appetizer, like these four-ingredient pinwheels.

15. Culture-Hop All Day Long

On Saturday, September 28th, you can get into 1,500 museums across the country for free, as long as you fill out and print this ticket. The $21 will come in handy for gas, lunch and a commemorative, flattened penny emblazoned with your favorite museum's logo.