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.

1. Play Pen Pals with Your Future Self

No, we're not talking about the cryptic faxes Dwight received on The Office; with Seeds of Thought, you can write a letter to yourself—or anyone else—and for $15 or more, the company will mail it to you three to 20 years from now. It's a time capsule where you can store the one thing you don't want to forget, and the one thing you want to have accomplished by 2016—or 2033.

2. Take Part in a Collective Runner's High

As fun as they are, the multicolored, chalk-hurling, mud-slinging, army-crawling 5Ks that have become so popular can also come with a sizable registration fee. You may not look like a human tie-dye experiment at the end of a local charity run—like this Wipe Out Kids' Cancer 5K in Texas—but fundraising races often offer early-bird registration for $15 or $20.

3. Make Cross-Country Homemade Cookies

Buy the ingredients for your favorite treat—we love this chocolate chunk variety—bake a batch, then send the extra nonperishable ingredients (and recipe) in a mason jar to a friend.

4. Become the World's Best Babysitter

Treat your kids—or your niece, nephew or friends' kids—to an afternoon on the town. AMC and other movie theaters offer discount matinees ($5 to $7, depending on where you live). You can plan your adventure to coincide with a restaurant's "Kids Eat Free" night.

5. Channel Your Inner Artiste

Serious art class this isn't, but that's what makes a "Drink and Draw" night so satisfying: It's a chance to try your hand at sketching models (while enjoying drink specials), in a judgment-free zone. Bars and restaurants across the U.S. are starting to offer these events as an alternative to karaoke and trivia nights.

6. Upgrade Your Home with the $8 Miracle Table

When is a table not only a table? When Young House Love bloggers John and Sherry Petersik get their hands on it. With this straightforward tutorial, you can turn a set of tables into a headboard, shelves or a two-tiered bookshelf—and make your house feel a little more you.

7. Feel Good About Crossing That Cuff Bracelet Off Your Wish List provides at least 25 cups of food to people in developing nations with each sale, of everything from scarves and chandelier earrings to bamboo wind chimes and soup bowls emblazoned with chubby cats. Plus, you can click the "Donate Now" button each day and the site's sponsors will donate food for free.

8. Ditch the Dinner-and-a-Movie Third Date

...for an afternoon at your local bookstore with one objective in mind: Each of you must find a book you think the other would love. "You'll learn so much about each other, and it's a great way to show that you've been listening to what the other is passionate about," says Jess Buscemi, half of the blogging duo behind Afterward, head to a coffee shop and talk about your picks.