Shameless rip from Slickdeals:
Coworkers are all using the same AGP All-in-wonder around the workplace to register. Integrated ATI seems to work too.
...you get both Half-Life 2: Lost Coast and Half-Life 2: Deathmatch for free if you're the owner of a Radeon card. Does not have to be a made-by-ati card, it can be from the other resellers as well...
Here's the link to the offer: http://www.steampowered.com/ati_offer1a/
P.S.
You need to either have Steam or create a Steam account in order to be able to download the content since its all done through Steam.
Coworkers are all using the same AGP All-in-wonder around the workplace to register. Integrated ATI seems to work too.