Pygame seems a sensible choice. I don't think it's wise to focus too much on the technology for the contest (unless you were planning on focusing on technology anyway and just needed a project to work towards, of course).

I read your earlier post where you were looking for some music ideas. One suggest I might have for freebie music is Kevin MacLeod's Imcomputech site; it's got a lot of nice tunes. For a Wild West theme my guess is the best fit would be the Silent Film Score section; it's got a lot of old timey piano music that might work for a western.

Thank you very much for the music site!