In python, 30 lines: <a href="http://billmill.org/pong.html" rel="nofollow">http://billmill.org/pong.html</a><p>(edit: I just mean to offer for comparison to this program, not in some sort of macho programming-language pissing contest sense.)
Just today I was tinkering with dreamscheme and its SDL hooks, thinking about writing a pong clone, wondering if it would gain any attention after Haskell pong has.