Steam now offers a playable demo for MXGP - The Official Motocross Videogame, the installment in the dirtbike sequel that will be released this week (thanks Frans). Here's word on the contents of the demo:

Available tracks: Great Britain – Matterley Basin.
Riders: Antonio Cairoli, Clément Desalle and Gautier Paulin.
Quick Race: a double race, with no qualification and custom difficulty setting. Players can also have a sneak-peek at the menus and the tutorials.
The release date of the home console version of the Demo will be announced later on.