If you are not familiar with the concept of flow (à la Mihaly Csikszentmihaly), then you may want to crawl out from that rock you have been hiding under for the last decade or so. Essentially it is any activity capable of causing fluctuations in one’s sense of time and self: surfing, jogging, drawing, writing, mountain hiking, meditating, poker, video games, high-quality tv or movies, clubbing, or various shortcut chemicals and plant-derived substances (the last few I do NOT recommend).
Personally, meditation has provided the strongest creative bursts, usually following a day or more of intense meditation. Mountain hiking also has historically been very beneficial, or any other solitary exercise-jogging and walking included.
If you are creative, working in a creative field, or wish to develop your creativity further, then I highly recommend finding some sustainable ways of incorporating flow into your daily life. Why do I mention sustainable? Depending on the activity that you use to instigate flow states, you may be doing harm to the other parts of your day/week. Just like a sugar rush, there is eventually a crash, unless one eats natural sources of sugar. Thus the point is to be as natural as possible in your pursuit of flow, and the only natural and healthy ways I know are exercise in nature (surfing/body-boarding and mountain hiking are best examples) and meditation.
Just as Jedis must be mindful of the dark-side of the force, you must also be mindful of the dark-side of flow. A natural approach in seeking it out can ensure its beneficial nature will not do harm.