Smart kids start saving for retirement early.

If your work offers it, put money in a 401k as employers often match contributions. No 401k, start a Roth IRA instead. Invest aggressively, with 90% in stocks. You're young, and you've got time to sit out dips in the market while enjoying the historical 10%ish growth.

Bankrate says, "When you are in your 20s, a small consistent investment even for a short period trumps starting later and investing more money." — BEN POPKEN

Retirement planning for 20-somethings [Bankrate]