The Horizon programme is being aired again late tonight on BBC2, at 11:20 except Ireland where it's 11:50.

Horizon: The Creative Brain - How Insight Works
The work of scientists who are adopting unusual techniques to try to determine how flashes of inspiration come about, developing a series of puzzles and brainteasers to spark creative behaviour. The latest neuro-imaging technology means researchers can witness the birth of an idea as it happens and what they are learning has the power to make everyone more creative.