What was the very first game added to your Steam library?
To find this info select menu: "Steam" -> "Settings" then click the "Account Details" button, then click the "View licenses and product key activations" button. Scroll all the way to the bottom and show us what ya got.
Here is mine...
The ATI Bundle was a bundle that came with certain ATI cards that offered Half Life 2 when it came out. When Valve announced that the HL2 release was pushed back, the people with the codes were pissed. So, to placate the riled masses, they gave out the ATI Bundle which included the original Half-Life, Counter Strike, Team Fortress Classic, Deathmatch Classic, and Half-Life: Opposing Force and Ricochet.