Heh, Freeman

I was playing S.T.A.L.K.E.R: Shadow of Chernobyl, and finally found the Gordon Freeman easter egg. He's laying down dead in a tunnel in Wild Territory. There's shocker anomaly's everywhere, so be careful if you go for a look. He's got short hair, glass's and a goatee, and is called Freeman.

There's loads of games which make Half Life references now. Splinter Cell, Destroy all humans, Stalker, even Lost(the show, not the game).