If you hit a brainstorming block, the solution is to do anything *but* brainstorm.

Wander, physically or mentally. Research has shown that allowing the mind to drift leads to the formation of more inventive links among pieces of knowledge we possess.

There's a reason why the 10th largest community on Reddit — with 30 million members — is called Shower Thoughts. The shower is kind of an "epiphany incubator" due to the relaxation and redirection of attention.