We were over at a my friend Dave's, who had a whole lot of D&D 3 books around and a bunch of people were there who had never played an RPG. I like the art in a lot of 3e books, so I told everybody to find a book they liked and pick some picture of a vaguely humanoid dude they liked. Everybody did, except for Patrick who found a picture of a Neogi and was really adamant about playing a Neogi and I said fine except that he would have to be about the size of a guinea pig and he was fine with that.
Then everybody took a sheet of paper and I said to write down three sorta-specific things that they thought their character would be good at, and three sorta-specific things that they thought their character would be bad at. I then told them to write a little +1 next to two of the good things, and a +2 next to the other, and a little -1 next to two of the bad things, and a big -2 next to the other.
While they did this, I pulled up Untimately's random dungeon gear chart and my own list of random first level spells. I assigned everybody gear, then I rolled a 20% chance to see if each character had magic. If they did, I gave them a random spell from the magic list, which they could cast once. I just had them roll 2d6 for HP and for attacks we just rolled a d20 (with a bonus +1 if they mentioned something about fighting in their description). There were adjustments allowed for weapons to fit their description, and I pointed out that being good with a bow doesn't make you necessarily good with an axe, etc., and we were ready to go!