YES YES YES, and it's been happening since I started college. I've notice it comes when I'm sleeping AND when I"m awake. Doing the times I'm awake, it's usually during long road trips or plane trips and in a lecture when I'm not paying any attention. They're very intense, like someone turn on a switch and all of my senses are heighten. I'm 34, my doctor feels its the vibration of the plane or car but it doesn't explain the times when I'm just sitting in a chair reading or listening to a lecture or song. My doctor also suggested that I may have increase male hormones that explains my increase libido. I've done my on online search of the matter and you problem have better luck under the title of "extragenital orgasm" instead using the word spontaneous the studies seem to interchange the term. This one paper even suggested that it can occur during breast feeding, while a hairdresser shampoo your hair, even looking at a scenic picture: www.psychosomaticmedicine.org/cgi/reprint/16/3/240.pdf
I've also found that certain medications can cause spontaneous orgasms as a "side effect" and also seizures of the temporal lobe : emedicine.medscape.com/article/1186872-overviewhopes this helps, and ur not alone
(From the Sexual Issues: Member to Member)
via forums.webmd.com