What do you say when an interviewer says, ';tell me about yourself';?

I was asked this question in an interview, and kind of froze. I said where I was from, where I go to school, and what my major is. Then she just kept looking at me expectantly, like I was supposed to say more, but I didn't know what she wanted to hear! I was tempted to start talking about how I was a cheerleader in high school and all that crap, but I thought that would make me sound immature and ';stuck in high school';(I'm 20 and a junior in college). Any advice?