Earlier this spring I planted broccoli, along with a bunch of other brassicas (stuff related to cabbage). Although little heads started to form, they got leggy and tall and went to seed before ever really developing.
Along with my skinny, flowering broccoli I planted cauliflower -- which hasn't formed any heads yet -- and cabbage, which is still a collection of loose leaves. My Brussels sprouts have also yet to show anything more than a few loose leaves, although I'm pretty sure that my husband has been beaming bad thoughts to the Brussels sprouts every time he's outside, so maybe it's working. ;)
I haven't grown most of these plants before so I thought it was something I did wrong, but I was at a gardening class yesterday and found others who are in the same boat. We speculate that the weather this spring may be the culprit. I don't know if the amount of water was a problem, or maybe it was the lack of sunshine. Other than the lack of vegetables, the plants seem to be pretty happy so I guess I'll just wait and see if they do anything before the weather turns too hot.