Last week, pranksters dyed the Goldstream River on Vancouver Island bright green using the dye fluorescein. Apparently the river was so bright that it was painful to look at. Here's footage of this roiling ectoplasmic channel.
A fountain in Langford, British Columbia also received the green treatment. Here's a news report of the incident — you can see a clip of the fountain around 1:50. Fortunately, it looks like the ecosystem won't be rattled by the pigmentation, but the dye can have nasty side effects in humans.
[Via Yahoo.ca — thanks, Wolsheim!]