What I do is go out side jump around a bit and scream while throwing the computer around by the cords...

For the most part I make sure I take breaks, focus on a few different projects at a time so im not always on one thing which sometimes get a bit monotonous. Everyone goes through it i had a bout last week.

The biggest thing is to make sure you have a life outside the computer. Like sports or a hobby.

I try and spend as much time with my wife going out doing things like movies. Helps clear the mind and she actully helps me focus on new ideas when im on brain drain.

Main thing is to get your mind off the project for a bit and come back to it with fresh eyes.