Advice for first hackathon

I'll be going to LA hacks for the first time. I know some C++, Python, R, and Matlab, and I've dabbled with web programming as well as some machine learning but I'm not sure what I should be expecting at a hackathon. I just want to make sure I'm prepared to have a good time and not just be frustrated the whole time. What advice do any of you have and what do you think would be good to brush up on in the next week? Thank you!