Although it might not be the best fallout rpg as such, it is a solid shooter and with mods extremely playable, once geck is out, should be even better

Post-Apocalyptic FPS/RPG set in the ruins of Washington DC after a global nuclear war. Be what you want and play how you want. Skyrim with guns!

This game and Fallout 3 are what got me into gaming. Not nearly enough characters to explain what makes this game great, but it is an awesome RPG.

Probably the best zombie game I have ever played. All about finding ways to survive rather than using OP weapons to massacre zombies. Also Parkour.

Same as Don't Starve, but with friends. Eating the last piece of food in front of your starving friends = priceless.

A hardcore survival simulator where you do what the title tells you not to do over and over until you figure things out or you die horribly another way.

Grab some friends or find some randoms and rob some banks, collect some masks, and watch as your offshore bank gets a ridiculous amount of cash.

A 2D sandbox where you can build, mine, and fight. Go mining to get gear to kill bosses to get gear to kill stronger bosses. My personal favorite.

Awesome co-op rpg with guns. If you can get a friend or 3 to play this with you it can be one of the best co-op experiences you will ever have.

A fun, voxel-based MMO. Plays like Cubeworld (Mix of Minecraft and Diablo if you don't know what it is). Good game to hop on and waste some time in.