Every winter Steam does a fantastic sale where they sell all kinds of PC games at discounts that just aren't found anywhere for most of the rest of the year. So I indulge. This results in additions to the backlog, of course. Here's what's landed on it thus far this year:
Defense Grid: The Awakening
Iron Grip: Warlord
I also got VVVVVV, World of Goo, and Doc Clock, the Toasted Sandwich of Time with the bundle I purchased. I may give VVVVVV and Doc Clock: The Toasted Sandwich of Time a shot at some point, too, but right now they're just bundle extras to me. World of Goo might make the backlog at some point - the steam version appears to play nicer with my multiple monitors - but for now I'll stick with those three, plus whatever else catches my fancy in the sale.