My birthday treat to myself was The Orange Box expansion for Half Life 2.
As well as including Half Life 2 and the Episodes 1 and 2 expansions for it, the key component for me was Team Fortress 2.
TF2 is an online shooter that follows on from a really old Half Life mod called Team Fortress Classic (a conversion of a Quake 2 mod called Team Fortress - surprisingly). TFC had been my favourite online shooter of choice for many years and the TF2 update for it is just as much fun.
The game play is pretty much identical and the new graphics engine is brilliant (cartoon style rather than super-realistic). and overall it makes my purchase worthwhile!
However The Orange Box had a bonus... A technology demo called Portal which had been converted into a game. The game is a "not too tough" puzzler and has only about 5 hours of game-play too it, but the work they have done to add atmosphere and a plot to the game are just brilliant. As far as freebies go there is no comparison - this one rocks!
The Cake is a Lie!