If you're a Penny Arcade (http://www.penny-arcade.com) fan, you probably already know about the Rainslick Precipice of Darkness: Episode One. It's the result of an unlikely trajectory from webcomic to action/adventure game. The Tycho and Gabe characters take over a 1922 Cthulhu-esque world and... probably swear a lot. Beats me. There are guns, too.
It's finally available here: http://www.playgreenhouse.com/game/HOTHG-000001-01/
But I'll be waiting until I get home and grabbing it through XBLA.