I use a raynox wide-angle, I've got a couple of 0.3x's and a 0.5x, they cost about £27 each.
You can get them from a Jessops shop, or http://www.jessops.co.uk.
They just snap-on, which can be annoying because they can work themselves loose, but it doesn't happen very often, they're also really tough, one of mine got run-over and left outside all night and it still works ok, although with a big scratch on it.
I'd go for the 0.3x for skating, that's the same sort of effect as a century "death" lens.
Panasonic SD9, Panasonic NVGS-75, Canon MV600i