Kennichi's right... take up a sport if the gym isn't really your thing.
For a while, I was lifting a lot and got really into it. Took a bunch of supplements (pre and post workout, protein, etc...) and got really fit, strong and HUGE. I had to stop cause it was causing some serious damage to my health as I was losing sleep and what not from all the supplements. I have stopped since but am still lifting regularly.
One of the supplements I started taking back then was called Axis-HT from BSN. I found that it increased my libido by a ton! I was actually having sex 4 times a day and if I can't get my hands on my gf or a WG, I'd feel the NEED to jerk off.. It was getting out of hand (no pun intended) so I stopped that but because of everything else I was taking, I was still wanting to have sex at least once a day.
Here's the link:
http://www.bsnonline.net/details/axisht.html
Before trying, you should probably consult a doctor. This stuff is pretty potent. I'm not sure if Axis was the thing that was causing my heart to jump faster than normal or one of the other things I was taking but for a time, I couldn't even sleep cause I was too full of energy. One time I had to go for a hour run at 2 in the morning cause I couldn't sleep and was all jumpy.