While I wholeheartedly agree with fnid (see his sibling post) that you won't actually learn anything until you are scratching your own itch, the most fun way I

While I wholeheartedly agree with fnid (see his sibling post) that you won't actually learn anything until you are scratching your own itch, the most fun way I can think of to learn to program is to make a game. Flash (and actionscript, which is akin to Javascript) would allow you to do that with graphics... but if you don't want to mess with that, just make a text-based game. Something simple like two player tic-tac-toe with an AI, just displaying a new board after every move, would get you a long way. Python and Ruby are good languages for things like this... as is Scheme or Javascript.