Stuntman: Ignition

All that is required is to host 50 matches. It doesn't matter if you win or lose. The fastest way to get it is with Movie Challenges boosting with a friend. Create a ranked session, choose Movie Challenges, and then choose 6 scenes. At the beginning of each scene, drive in reverse to fail immediately; if reversing doesn't work in the scene, just fail as quickly as possible.

Despite the wording of the achievement description, each scene counts towards the achievement, so you'll need to host about 9 six-scene matches to unlock the achievement.

(If done as part of a boosting session for all the multiplayer achievements at least on person will get this hosting the games for the other achievements.)