Steaming them forever would be a lot better than boiling them, because less nutrients would be lost.
Also, the recipe for brussel sprouts that was posted by someone last week (sorry, can't remember who!) is very forgiving of extended cooking. Saute brussel sprouts in bacon or butter, then smother in cream. Cook till done. They're good whether still having some bite or if you let them stew till mushy (which I find miraculous for any cabbage-like veggie, which usually gets awfully stinky if cooked for too long).
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food