I'm toying with the idea of releasing my NorOps mod on April 1st and give the announcement thread 'NorOps canceled' as a header, with a big blue crying smiley. Then, once the saddened forum members open the thread, they're greeted with the 'April Fools!' line and a download link.
Would be awesome if a dev team did something like that. Pretend to suddenly be going downhill for a week or two, for then to 'cancel' the mod - and then release it. Might be a very bad idea, though.
"One of the bitches actually gave birth while she was attacking, and her puppies joined in on the carnage."
--the awesomeness that is Boatmurdered.