Kult

The short description of Kult would be "Call of Cthulhu: This Time You Can Win!"

The fluff basically goes that humanity were once the supreme deities of creation until the Demi-Urge tricked us into forgetting our divine powers and convinced us we were basically mortals. Severe mental trauma, seeing shit that CAN'T BE REAL and so forth can knock people out of it and help them regain their divine powers(of course, odds are they'll go screaming insane on the way and just end up as demi-gods in some private little hell that's permanently collapsing on them).

The basic mechanics are D20, based on rolling lower than your various abilities, the farther you roll below a skill, the better(example: you have 15 in a stat, rolling a 5(10 below) is better than a 12(3 below).).