It's Monday afternoon, and we're all bored out of our minds by spreadsheets (that's why you're here, right?). Nuke that boredom right in your browser with Markus "Notch" Persson's new free game Shambles, part of the seven-day FPS creation challenge.
It's coded using Unity, but if you've played any other browser-based game recently you'll probably have it installed already. Essentially, Shambles is a zombie survival shooter with the pacing of Doom; run, gun and get the heck out of dodge to survive. Just don't shoot the police or the civilians.