Okay, there is this girl who has the same teacher as me for Core, but we don't have any of the same classes. She is intelligent and has a large group of friends. She is pretty and outgoing, but she isn't ever mean-spirited. The first time I really paid any attention to her was when we were setting up the classroom for a project that both of our classes were working on, she didn't seem to be acting weird, she just smiled a lot. After we finished up I went back to work before the period ended and she stayed back with some of her friends, whenever I would look up at the clock or whatever that was right beside where she was she would seem to be dancing, or fooling around but when she saw me she'd continue but smile well doing it. A couple of days later well we were outside and I was playing football with a group of my friends. She walks over with some of her friends and asks if we would let them play, we toss it back and forth and one of my friends who knows I like her said "Aaron, Allie throws a hell of a lot better then you." Rather hastily, I replied "I know, she might take my spot on the [co-ed] flag foot ball team" The only reply from Allie or her friends was a few awkward laughs.
Anyway, it's about two months since that happened, and she didn't talk to me at all for about a week in between then and now, and today she seemed to be subtly avoiding me, any thoughts? I am pretty sure she at least liked me two months ago, not so sure now.

Most girls do generally smile a lot and make fools of themselves. It probably seemed like she was into you a lot but it may just be her happy & upbeat personality. You will never no unless you ask her to hang out more often.

Yea, I have been trying to talk to her for a while but she always seems to be with a group of friends. I mean I have talked to her before, and I danced with her at the school dance but she isn't around enough to try to talk to her. I asked her if she wanted to go see a movie with a group of us from the school charity council, but she said it was to late notice and she couldn't. I've been trying to find another reason to get a group of us together but I can't and I don't know her msn, or even if she has one.

She most probably does have msn/myspace/facebooc etc etc

Yea, but what IS it... thats the only issue here

ask her O.o

Yea asking her would be pretty easy or if you have facebook/myspace look through your friends to her friends sorta thing. Like a navigation. Its not hard & its the whole point of those sites.

she sounded interested in you 2 months ago.
i generally do that when i like someone, i smile and laugh and im happy with my friends.
ask for her msn.
what have u got to loose?