It's appropriate on both counts that the first official confirmation of Far Cry 3: Blood Dragon comes on April Fools' Day and is totally warped. This teaser video and a new website, both revealed today, indicate some kind of 80s-styled take on the island setting of Far Cry 3.
The website's "Story" section, for what's advertised like a movie, reads: "The year is 2007. It is the future. Earth has been ravaged by a nuclear war and new paths for peace must be found. A U.S. cyborg army may have found a solution: a powerful bioweapon on a distant island. A Mark IV Cyber Commando, Sergeant Rex Power Colt has been sent over to gather information and figure out what the hell is going on."
As with everything today, take what you're looking at and reading with a great big grain of salt. On the other hand, we've seen plenty of evidence FC3: Blood Dragon is a genuine standalone continuation of Far Cry 3. It received Brazilian classification ratings for Xbox 360, PC, and PS3, there was leaked XBLA art which matches with today's reveals, and a list of achievements recently popped up too.
Also, in relation to a possible Far Cry 3 continuation, Far Cry 3 lead writer Jeffrey Yohalem recently told us "I'm working on something now that will be surprising, I think, when it's announced. But it definitely is a 'strike while the iron's hot' thing, and we'll see."
We've reached out to Ubisoft for more details.
Update: As clever commenter Nhauga spotted, if you enter the Konami Code while on the website, your cursor turns into a crosshair. You can use that crosshair to shoot up all of the site's gaudy 80s-ness, eventually leaving you with this mysterious gif.