Stuntman: Ignition

The above method DOES NOT WORK!!. We tried it tonight and only the one hosting got the achievement.

To get this all we did was start a movie challange and then we all drove off the set, this gives the HOST a win, also counting towards your 50 hosts too.

I hope this helps everyone, nice and easy and can be done with just two people.

Grab a friend or boosting partner and host a ranked movie challenge which is basically just replaying single player levels trying to see who can get a higher score. Then get in first place 20 times to unlock the achievement.

Something that can make this go much quicker is if you and your friend simply drive out of the scene and the start of the match. While you both get a score of 0 and Even though you both have technically failed the scene the game will consider you both to have been in first place. Instead of having to do it 40 times, you can just do it 20 times and you both get the achievement.

This is also one of the fastest ways that I know of to get the "Host 50 ranked games" achievement.

To earn this achievement, you'll need to win 20 movie challenges (not necessarily in a row).
Online is abandoned nowadays, so you'll need to boost it.
It's possible to start a match with only 2 players in total (you + one boosting partner).

From the main menu, go to Multiclash, Xbox Live, Ranked Match, and create a match of the "Movie challenges" gametype with just 2 players.
Now add 6 times the challenge titled "Rain of terror"
In case you're wondering, each match of 6 rounds will count as 6 wins in total, and 6 hosted matches, helping your way to

As soon as the match starts, both you and your boosting parter will have to keep (retro) pressed, so the match will end almost instantly. The player with the most points earned will win the match (even if it's not the host), but if you both have the same points (as for the example), the host will get the win.

NOTE: If you already have the hosted matches achievement and just need to win matches, while your partner just needs to host, let him host: you'll have to accelerate in straight line 'till you'll fell down from the starting broken bridge (few meters ahead from start), while he will have to press (retro).
Be sure to earn at least 1 point (!) in the process, and you'll win the match, while he will earn an hosted match.