For that money you're going to want a camcorder. You won't look as cool to your friends but it will produce better footage than any DSLR under $500. You could get a T3i if you only wanted a DSLR, but you'd be stuck with the kit lens, and you want something better.
Just some quick research got me this bad boy: http://www.bhphotovideo.com/c/product/910268-REG/panasonic_hc_v720k_hc_v720_live_streaming_hd.html
1080/60p, and Panasonic is known for great video cameras, between the GH2/3 and the likes of the TM700 and such. It'll be solid, and the image quality will be excellent. The 60fps will do very well for slow motion too.
Hello future me,
I had no expectations for you. So anything you have done is a plus for both of us. Good job! -iAfterBang
My Visual Concoctions