So I've decided to make a randomized metroidvania game; sort of a cross between a roguelike and one of the greatest games ever, Castlevania: Symphony Of The Night. Since I want this to be a flash game, I'll use Eclipse and Flixel.
I spent a few hours getting Eclipse to work with Actionscript and playing with Flixel a bit. For my game I decided to start with generating a random world map.
Here's the basic algorithm, which took less time than setting up Eclipse and Actionscript:
add a 1x1 "frontier" space
add a room
to add a room:
randomly pick a frontier space
start a room there
randomly grow it for a while
remove frontiers under it
add its empty neighboring cells to the list of frontiers