Well, I'm actually a bit odd. I'm really energetic in the mornings, and really energetic in the late afternoons, but I have a beast of a time around the middle of the day - especially if I had any sort of sizable lunch. I've tried suggesting a siesta break, but no one else really seems to go for it. But either way, I'm most creative when I have the opportunity to get up and move around. When I'm stuck on something, I'll often get up and pace, or even take a little walk around the building.