You might've gotten notifications of completing seveal Forzathons events and wonder what is going on. A configuration error happened during the last batch of Forzathon events were published, so everything went live rather than being time-staggered as done previously. Per last week's Week in Review, these will all be available until May 11, at which point a new set of events will roll out and follow a proper schedule. So, feel free to go grab a bunch of stuff while you can!
If you would like to know what they all are, head over to TrueAchievements for their full list of FH3 achievements.