Though this is not the best or most dramatic Mayan ruin in the area (that title belongs to Tikal in Gautemala), this is worth your trip if you have limited time and don't want to travel far. We booked this trip on through our hotel. We basically paid the full fee at the hotel and took a plane to Belize City from San Pedro. Then there was a guide/driver with a nice minivan waiting for our arrival to drive us to the ruins. Usually, this should've been a small group tour, but the day had started with torrential rain so we luckily had a private guide. The drive took about one hour on mostly dirt roads after leaving Belize City.
The area was a jungle, very remote and deserted. Our guide pointed out different types of trees, fruit indigenous to the area. When we arrived at the ruins, we were the only ones there! He gave some historical background and helped us take photos. There was the big Temple of the Masonry Altars, which we were able to climb (precarious steep steps, don't attempt if you are afraid of heights) up to the sacrificial level...it was amazing to think that 10,000 people inhabited this site, apparently in 900 BC (not exactly sure about the date, but I remember it being an astonishingly long time ago!).
On our way back, our guide stopped by a local supermarket where we bought some local herbs. We bought some small bags of 'Feva Grass Leaves,' dried grass-like leaves to drink with hot water. Smells wonderful, just like lemon tea. Our guide said it cleanses your system.