[How to: TV] Brainstorming Characters

We had another brainstorming session last night in which - due to lack of sleep - I was Mr. Grumpy. However, we roughed out another good idea for a TV series and in the process I thought of several things it'd be worth brainstorming when you are designing characters.

Career, Character Traits and Secrets.
Trajectory (or Destiny). Chris suggested this; it's where a character appears they're going to end up, at the start of a show.

Then I think you should brainstorm 20 Facts everyone's sure of about the character, 20 Ideas or wild possibilities for them, and 20 Questions that nobody's sure of the answer to about the character.

After that brainstorming, choose the issues that seem most fundamental and go through brainstorm possibilities and solutions to those.

The point is: You don't want to settle for the easy option. You have to go deep so that you're convinced by the answers.