marc108, thanks for the recommendation about tea. Also, are you referring to polyphasic sleeping? i.e. limiting all sleep to 1.5 chunks to reduce total time spent sleeping? I have experimented with polyphasic sleeping and am always interested to hear others' experiences with it. I wasn't terribly successful on the schedule I chose - one 3.5 "core" sleep at night with 3 20 minute naps throughout the day. On that schedule, every time I'd try to meditate I'd invariably drift off, so I'd always meditate right before naps. Eventually I gave it up though and found that my mindfulness improved dramatically going back to mono- or biphasic sleeping.
ps. LOVE that sleepytime website -- thanks! I am well aware of how waking up at different parts of the sleep cycle affect my perceived levels of drowsiness and sleepiness. This is an awesome tool for quick calculations!