There are a good number of options, though I'm sure you already know that alternative sleep schedules are largely untested (we're working to change that). There are a lot
of threads here on the Health and Fitness forum regarding biphasic and polyphasic sleep, with a lot of questions and answers that might help you to figure out what kind of schedule would work best for you.
That said, I'll give my own recommendation: since you're in school and almost certainly living at home, I would recommend biphasic sleep--it's fairly easy to adapt to, not too revolutionary (i.e. it won't freak out your family too badly), pretty well proven, and will almost certainly reduce your sleep time, possibly in the short-term and almost certainly in the long-term. As you say, "full" polyphasic sleep (such as the "Uberman" schedule that Steve Pavlina used) is unlikely to be compatible with your current schedule and living situation.
So for biphasic sleep, you have two sleep periods during the day, usually with one long "core sleep" during the night, and a shorter nap during the day. I highly recommend that the lengths of those sleep periods be multiples of 90 minutes, basically because 90 minutes is the length of the average person's sleep cycle, and it's best to wake at the beginning or end of a sleep cycle (for a full explanation, see this article
). When you're just starting out with biphasic sleep, I would recommend a schedule that includes four or five sleep cycles. That's 6 or 7.5 hours of total sleep, usually in the form of a 4.5-hour or 6-hour "core sleep" at night and a 1.5-hour nap during the day. Later, you can try cutting down to less sleep cycles (I'm not sure if three sleep cycles is feasible long-term, but four cycles almost certainly is). Also, I've heard that as your body gets more used to the schedule, the length of each sleep cycle decreases slightly, so that you could eventually get four sleep cycles in 5 hours instead of 6.
One suggestion that will help you regardless of what sleep schedule you adopt is to be consistent with it--i.e. get the same hours of sleep every night, even on weekends. This helps with monophasic sleep, but with biphasic sleep it's much more important, and on polyphasic sleep it's practically essential. If your sleep is consistent, your body can work on optimizing it, at least improving your quality of sleep and maybe even reducing the amount needed. When you start waking a few minutes before your alarm goes off, you know that your body has become well-adapted to your current schedule.
I'm looking forward to seeing what you decide to do and how it works out. If you choose biphasic or polyphasic sleep, please write about your experiences in the polyphasic sleep logs
thread so that others can learn from them. Good luck!