I've been brainstorming with Critter in an effort to generate more high-impact ideas at work. Something he came up with that I'm excited about is a Stupid Ideas List.
The idea: whenever an idea occurs to you, no matter how stupid or insignificant, write it down. Keep a list of all your stupid ideas. Take some time to actively come up with some ideas without thinking about how good they are.
I was actually sort of in the habit of this a few years ago, where I would sit down for an hour a week and generate a list of 10 ideas on a theme. This came from James Altucher's Choose Yourself, he chose the number 10 specifically because it's easy to come up with five or six ideas, but by the time you get to 8, 9, and 10 you really have to stretch. Stretching is easier when the ideas are stupid!
This gets at two of my favorite tools for productivity: taking action and lowering your barriers. I can't count the number of ideas that have flown into and then out of my head without taking root, simply because I didn't think they were worth saving. What if I had taken ten seconds to write them down? How many good projects might have grown from those stupid seeds? Probably not many, but I'm sure one or two of them could have led to something interesting.
The thing about stupid ideas is that they seem stupid when you first think of them, but they can often lead down a path you never would have seen because you're too busy thinking of not-stupid-but-average-and-boring ideas.
I tend to generate ideas and edit them at the same time, a habit I'm always trying to break. Those are two separate steps, so in the words of the world's most surprising PhD: "keep 'em separated." You never have to show anyone how stupid you are during the generation phase, you can use the editing phase to make them think you've got Dexter-Holland-level smarts!