Borderlands is a franchise by Gearbox Software, and it is absolutely crazy. The main series of games offers up to 4 player "drop in"-"drop out" co-op, and with each additional player, the enemies in the game get stronger, but the loot gets better too.
The defining traits of the Borderlands series are 'Action', 'Humor', and 'LOOT!'. Lots and lots of loot. The tagline for the first game was "87 Bazillion" guns. That should give you an idea of how many different variations equipment has!
Join in with the community and spend hours making bandit faces explode as you search for the perfect gun (or shield, or Class Mod, or Grenade Mod, or Relic...Well, you get the picture)!