In negotiating his contract with Brawn GP for last season, Button reportedly agreed to a salary cut given the team's drastically reduced budget compared to the well-funded Honda years. A clause, however improbable it may have seemed at the time, was included in the contract that stipulated that, should Button win the championship, he'd be entitled to keep one of the cars with which he won it.
After the season was done, Button moved to McLaren and Mercedes bought the Brawn team, the chassis wasn't delivered. Offering instead to build Button a replica, the team reportedly claimed there weren't enough chassis to go around, so Button's company took the team to court.
The parties have reportedly since settled out of court and Button is due to take possession of his championship-winning car. But if you thought he had an easy ride to the title, claiming the prize apparently proved anything but.