good introductory game programming langage/library?

Today I helped Ben install Debian and watched him begin to learn basic unix commands. It's been so long since I learned unix, it's nice to recapture that fun learning process again. And reassuring to see a teenager drawn immediatly to the command line: as soon as the flashy keen gnome desktop poped up on his computer he wanted to know how to get to the terminal he had been playing with on Anna's.

So Ben wants to learn some programming, and he's mostly interested in doing graphics stuff, although not entirely. And he has some simple programs he wants to write, so he's primed and ready to learn. I think basic 2d graphics is enough, but I don't know what programming language or library to recommend to him, since I last did graphics on, approximatly, the Atari 130 XE. An equivilant of which would be fine, I think he'd be happy to start with simple sprites, point and line drawing, etc.

So far the best fit I've found seems to be pygame. OTOH, Ben has been learning just a little perl already. But I'm pretty much open to anything, as long as it's free software. If I recommend non-free software to him it would probably be some macromedia thing since I've seen people experimenting around with graphics in that in exactly the right way.

Any recommendations?