GURPS, G.U.R.P.S., acronym, product name the Generic Universal Role-Playing System, a flagship product of Steve Jackson Games. [GJ1]

Addendum: One of the earliest point system role-playing games, it is heavily supported, and genre books exist for a seemingly endless array of milieu; from sci-fi and fantasy to licenced worlds based on computer games and literary works. GURPS is noted for its extremely realistic (ie: deadly) combat system, and for encouraging arcane point juggling. [GJ1]
Addendum #2: [1] is the home site on SJG's website. It's currently in its Fourth Edition.