I've had lucid dreams numerous times... several years ago when I was trying to recall my dreams more clearly and vividly... haven't even tried lately, but they still come occassionally.
Interestingly, a few years back I started taking Melatonin to kick in the "go to sleep" signal in my head because I tend to ignore tiredness and continue doing whatever I've been doing (reading, surfin' the net, whatever). My roommate started taking it also and found it helped her get a pleasant, relaxing night's sleep also. The main difference was... I've tripped 100s and 100s of times, she never has, but I had no lucid dreams and she on the other hand said it made her have crazy, lucid dreams frequently.
Strange, eh? :think:

I haven't used Melatonin for a few years now, but I highly recommend it for it's ability to induce sleepiness (while NOT making you High) and because it does NOT produce ANY hangover effect whatsoever.