"I can't do that" - famous last words!

I've always know I can't write poetry, especially formal follow-the-rules poetry. Prose, yes. Prose I can do. But it has to be free-format.

But in the Knight Fight game forum, of all places, there was a challenge to write haiku about the game, complete with a beginners description of what haiku are.
http://board.knightfight.co.uk/viewtopic.php?f=9&t=4297
Three lines, syllable count 5,7,5. That's it. (Yes, when I did a bit more reading I realised that isn't it, but...)

So I wrote a couple. Then I wrote some more. Then I wrote some about how to write haiku, started answering posts with haiku, and did one in Latin... look, when your main "competition" is a thirteen-year-old Swedish boy, who's writing in his third language, sitting back and giving up is not going to happen. Especially when he posted plaintively:

why does nobody
post in this excellent thread?
Because I like it!

My latest says it all:
Haiku? Addicted?
Who, me? I can give it up
Any time I like.

Then someone started us on limericks
http://board.knightfight.co.uk/viewtopic.php?f=9&t=4891

I've tried to write limericks before. I've failed. I've now done two in English, he's done six (I think), one of which slid into Swedish at the end, and my last one was in French. I can't write French either.

As a fictional friend of mine tends to say: "what's this word "can't"?"