Someone asked that on facebook. I posted a comment in answer, but it somehow never posted.
Here’s what I said:
constraints and buy Oblique Strategy cards.
In other words — make it so that you can’t make anything. Give yourself constraints, limits, challenges.
The Oblique Strategy Cards were created by Brian Eno and Peter Schmidt. You can buy them here: http://www.enoshop.co.uk
and learn more about the history and various editions of the cards here: http://www.rtqe.net/ObliqueStrategies