From Halopedia, the Halo wiki
4orty2wo Entertainment (sometimes rendered as 42 Entertainment) is a company that creates large interactive games as publicity stunts for other products. Their form of advertising blurs the line between fiction and reality, causing wide-spread user involvement in the campaigns.
I Love Bees
In 2004, they made the game I Love Bees to advertise Halo 2 for Microsoft and Bungie. Other games include The Beast to advertise the movie A.I., and MSN Found to promote the MSN Search engine.