Valve has announced that every game in the Steam store is now on sale. Titles in the catalog are discounted between 10% and 50%, which means you can now get games like The Orange Box for $38, BioShock for $41, and S.T.A.L.K.E.R.: Shadow of Chernobyl for $22. There's no need to get on this right away; the sale lasts until January 1st.
Thats pretty rad.