An alternative, courtesy of Anders Sandberg (via Kaj Sotala), is to set your alarm to ring two hours before your desired wake-up time, take one or two 50mg caffeine pills when it rings, and go back to sleep immediately thereafter. When you wake two hours later, getting out of bed shouldn't be a problem. Details here.
Coffeine doesn't work for ~10% of the population (like me).
ADDED:
I don't know exactly what's different and to what extent the effect exists but caffein doesn't have significant waking or alerting effects on me. At least not a 200mg pill (corresp. 2 liter coke or 2-5 cups of coffee). These I take to treat migraine where the caffeine does have a very notable effect on me.
..."Caffeine has a tremendously wide variation in action," Regestein admits. "The people who say 'I can drink a cup of coffee right before I go to bed and go right to sleep' ar
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.