Here is the full list of all 10 Kinect Sports Gems: 3 Point Contest achievements worth 50 gamerscore.
Reach level 1 (or observe another player doing so) to gain the rank of Preschool Player.
Reach level 2 (or observe another player doing so) to gain the rank of Jump Shot Wannabe.
Reach level 3 (or observe another player doing so) to gain the rank of Basketball Enthusiast.
Reach level 4 (or observe another player doing so) to gain the rank of High School Star.
Reach level 5 (or observe another player doing so) to gain the rank of Tear Drop Baller.
Reach level 6 (or observe another player doing so) to gain the rank of Fast Mover.
Reach level 7 (or observe another player doing so) to gain the rank of Bank Shot Hero.
Reach level 8 (or observe another player doing so) to gain the rank of Pro Player.
Reach level 9 (or observe another player doing so) to gain the rank of 3 Point Master.
Reach level 10 (or observe another player doing so) to gain the rank of Slam Dunk Superstar.