As if I haven't spent enough this year the steam winter game sale started last night and runs Dec 20 -> Jan 5th.
It looks today:
Prince of Persian series - 75% off individual titles
Wargame - European Escalation - 75% off
Mirror's Edge - 75% off
Scribblenauts Unlimited - 33% off
Borderlands 2 - 50% off
Borderlands GOTY - 75% off (thanks to diogenesl)
With some flash sales going on... not bad but could be better.