I love napping in the sun on a bench in my office building courtyard at lunchtime. The sun heats up the bench so that even if it is not so warm out it feels like lying on a heating pad. If I go out after 1 p.m. the courtyard is mostly empty and my favorite corner bench is all warm and waiting for me. Then I just have to lie down with my jacket hood as a pillow, put a hat over my eyes, and soak up the warm goodness. Ten minutes continuous actual sleep is usually the most I manage, but that's a good enough break in consciousness to refresh me for the afternoon.