Well first, is it high school or college?
The great part about either is that they give you room to be totally out of there and ridiculous. I don't recommend this but to give you an idea of what I've done and how "out there" you can be:
1) Stolen things out of girls hands while they are passing
2) Once I threw ketchup packet at girl passing
3) Sat on random girls laps
4) Sit down with a random group of girls, and say "What's up?"
5) Backed into a girl once
6) Randomly sitting down at booths and helping out (like for the red cross for blood donation signups, or voter registration guys who go around getting people to register for politcal parties)
7) Participated in clubs I wasn't in (like honors society, ended up doing stuff like directly handing 200-300 sandwiches to homeless people)
#6 accidentally got me a job for the VP of administration of my school. Didn't realize until I was signing papers for employees. Whoops. Ended up participating in chair board meetings..
I've done a lot more but there's a lot of stuff you can do. If you don't want to draw attention just be like.. "Hey, I'm bored. What's there to do?"
The parking lot is surprisingly good too. You can just wave them down and be like "Hey, what are you up to?".
Find a place where you can mingle though, like the cafeteria. It's the best place to do social circle, because you'll meet someone. Then you'll see them another day with other people. Sit down with them and you make 2 new acquaintances. Rinse and Repeat (Lather?).