Game on! It seems Britney Spears has had enough of just her name being dragged through the mud in the custody battle for her kids. Brit has reportedly hired a private investigator to track her ex Kevin Federline, in hopes to dig up some much needed dirt. One source tells TMZ.com that, while Britney and Kevin were still married, Kevin would smoke pot and drink beer around the boys. Britney is hoping to get some of the same goods on Kevin now, to prove she's not the only monumental screw up in Sean and Jayden's world. Britney and Kevin's lives may be a complete circus, but these two are driving the clown car.