I'm with Graham on Make Frivolous Fun Things Day. I respect developers who come up with goofy jokes for April Fools' Day then actually follow through on them, though I'd like 'em even more if they made goofy things whenever they wanted rather than wait until the sanctioned day, a day when I'll be suspicious of everything odd even when its makers swears blind it is real.
So I was wary when The Talos Principle [official site] Croteam announced they'd added the voice of Serious Sam from the eponymous shooty shooty murderfest series to their quiet puzzle game. But no, they really have, and it's free for a few days. The game's on sale too.
The Serious DLC replaces the ethereal voice of Elohim with the gruff tones of Serious Sam actor John J. Dick, who'll growl his own silly lines at you. It also adds an alternate skin for yer robot, with Sam's shades and a few logos on its chassis.
A proper, serious expansion is in the works too.
Look, here's a video I found of someone playing a little with the new voice and skin: