Going out driving when you're sleep deprived isn't a great idea. But if you want to be more creative, it's a good move. Paul Petrone 's blog discusses the advantages of losing sleep and, in the process, losing the inhibition to be critical of your creative processes. Just like "beer goggles", you can slip on your "groggy goggles" and let loose a flow of creative ideas you normally might censure or think twice about.
Scientists agree that some amount of sleep deprivation can help creativity, and Petrone's blog explains briefly the reasoning. However, he cautions that chronic sleep deprivation is a health risk, and while it might help creatives, it's no benefit to those needing to make clear, logical choices, such as engineers and scientists.
All this comes as no surprise to me. I keep a note pad by my bed to grab those ideas that come while my brain is breaking down synapses, and groggy thoughts abound. My best ideas often come from late night, daybreak, or in the middle of the night. You might found a more creative explanation, but I recommend you sleep on it first. What about you? Do you find your spark long after dark?