1. So you will have less to complain about next month
2. So you will have the right to complain about anything next month
3. To keep the crazies out of office
4. To prove you are not a nihilist
5. To demonstrate by your actions that you actually believe in participatory democracy
6. To prove the old folks- who say all young folk are apathetic slackers- wrong
7. So you can walk around all day with your "I voted" sticker proudly displayed, gloating and boasting about your implied political astuteness
8. So you can avoid coming up with a convincing lie to tell you friends and families when they ask you if you voted
9. Because Obama said to and he is commander in chief (if you believe in commanders in chief, that is).
10. To avoid letting the people who believe the world is about to end, who have already voted, and are voting in large numbers (because of their paranoia) to determine your future
11. To save soldiers. Historically, every time we have a Republican president or Republican majority in Congress there have been more wars and more loss of life.
12. To keep the Tea parrtiers out of office (Imagine Palin as your next president and then decide how safe it is to sit out this election)
13. Don't Ask, Don't Tell, Reproductive rights, healthcare reform, immigration, the economy, etc.
14. To keep the corporations from controlling our country (Ask David Koch)
15. Because you claim you are anti-racist
16. Because women died slow painful deaths by starvation in their protests calling for female suffrage
17. Because countless black Americans died so that all Americans could vote regardless of color, race, or creed
18. So our future can be better than our past
19. To increase the odds of having a representative who actually votes the way you want them to some percentage of the time. however small.