Suddenly, a spike in sales!
If you already bought Tomb Raider on Steam or do so before March 12, your Team Fortress 2 inventory will have three brand new Tomb Raider related items bestowed upon it. The "Tomb Wrapper" is a Scout-only item of a blood-stained bandage around his arm, the "Fortune Hunter" is Lara's pickaxe available for all classes, and finally the "Croft's Crest" is a badge for all classes, resembling something from the game I'm sure.
These items will likely be available to anyone playing Team Fortress 2, but those who buy Tomb Raider before March 12 will get the items in "Genuine" quality, which directly increases their worth in the TF2 market. With more and more players buying games mainly for the items though, these Genuine items are slowly starting to lose value.