I didn't have any experience before college. No summer camps, no jobs, no big projects.
I'm going into my senior year in college, working toward a BA in Biology, and just managed to grab a job in the ecophysiological/forest service department at the agriculture building. I'm doing stats on cycads (Cycas sp.) infected with the scale insect. It's pretty interesting even though it's only for 2 months. I hope to work with ants this summer, though, so I hope that goes through.
Check your university for research programs. RISE is one we have. My friends all tried it out and they think it's workwhile, especially on the CV. insane_alien is right in that you could help your professors with lab. You could TA if you want. Also, saying hello to your advisor and major professors makes you approachable to them. They could probably write awesome recommendation letters for you in the future! You're going to need it after college.