In the Ghostbusters game, character sheets are slightly larger than a 3x5 card, including room for a portrait. Characters have four Traits: Brains, Muscle, Moves, and Cool, and a Talent for each, which lets a player roll four extra dice when attempting a feat that falls under that Talent. Each character also has a Goal and a set of Brownie Points. The general mechanic is: to complete a task, the GM assigns it a difficulty and decides what Trait it falls under. The player rolls the number of dice their character has in that Trait and tries to equal or beat the difficulty number. The dice are all six-siders, and one must be the Ghost Die, which has the famous 'no-ghost' symbol in place of the six. If you roll the ghost, Something Bad happens, whether or not you succeed, and the ghost counts as a zero. If you succeed or fail without rolling a ghost, you just succeed or fail and nothing particularly special happens outside what you might expect to happen in that situation. But if you roll a ghost, even if you succeed, Something Bad happens, usually, in Ghostbusters, with comic effect.
Players can spend Brownie Points to improve their chances to succeed or to save their character's butt in an emergency. They earn Brownie Points by successfully completing adventures and by explaining what happens to their character when they save his/her butt with Brownie Points. Brownie Points are a little like Fate points, but they're also hit points: if you take damage from something, say, a poltergeist slams you in the face with a phone pole, you lose Brownie Points. I think it's a wonderfully compact and functional system that you can play without the need to look up things on a chart every 2.5x10-2 seconds.
I've made some notes on vague ideas for a sci-fi setting, a 'mutant animals living in our modern world a la Teenage Mutant Ninja Turtles' setting, and I've even pondered using this in a fantasy setting, and not only to wean some of my players from the idea that D&D 2nd Edition Skills and Powers is the only D&D ruleset worth playing fantasy in. And I'm really getting tired of Forgotten Realms.
When I've looked over the Ghostbusters rules in a little more detail, and decided if this is something I want to do or not, I'll update here.