What has worked for me in the past is an experience that combines intense physical exertion combined with attaining a difficult goal combined with an inspiring view. In other words, I hop on my bike and ride up a mountain and refuse to stop until I get to the top and bask in the incredible view. This has worked wonders for me in helping to gain real perspective on my situation, and I think the physical exertion and intense focus needed to make it to the top of the mountain help "reboot" my brain. Another method, during the winter, is cross-country skiing. (In the Bay Area, we have the largest X-country ski area in North America 2.5 hours North of SF.)

The bottom line, you need to completely focus on something entirely different than your problem at hand to give your subconscious a chance to recuperate and give you a solution and new inspiration.