What do you notice is different when you mess with your "normal" 24 hour patterns? Lately, because of the flexibility in my life and schedule, I've been able to experiment more with my circadian rhythms.
For example, I've been going to sleep and getting up at different times and I've also purposefully varied the number of hours I sleep from day to day. With the change in sleep patterns, my meal times have become fairly unpredictable; I find I'm eating a little less. For many years if I tried to read at night, I'd fall asleep easily. Since starting this experiment, that doesn't happen as often even when I have an early a.m. commitment. I also find I'm writing more in my journal and otherwise.
4:00 a.m. is kind of magical. Even when I played music for a living I would rarely be up at that hour. The other day I took a walk at 4:00 after reading and playing my guitar through the night. I felt really alive. The next time you have a chance (a weekend, a vacation, etc.) try experimenting with your circadian rhythms just a little. Then tell me what you notice.