I left a soda can in my car when it reached the low 100's, and now its expanded and warped the can. Do you think it is safe to open it now that its cooled down in my house, or will it explode?

As long as you open it away from you and over a sink.The worst that can happen is you get wet.

BANG. OK it is not going to take the side of your house out, it may shoot soda a foot or two at the worst.