I took a wonderful tour with Villa Siem Reap, or Beyond Unique Escapes, for $32 per person and it was well worth it. A friendly and entertaining guide, and an unforgettable trip out on the massive, and flooded Tonle Sap Lake (which is more like the ocean).
The Kompong Phluk floating village is unlike anything I've ever seen before; a whole community of people living on the flooded Tonle Sap Lake, and yet in the dry season, they are suspended in houses set on stilts. When we visited they were inundated with water, and we sailed past houses, where children fished from their doorsteps and floating supermarkets brought food and necessities from door to door.
The flooded forest is also a brilliant experience, where you float on a small wooden boat through a world of tree trunks and branches. Birds, frogs, rats, spiders and snakes can be seen if you look carefully enough ... and sailing through the tops of trees is quite surreal.
Had an amazing adventure with this company and would highly recommend it to anyone. The floating village is definitely not to be missed, and provides an excellent day's adventure away from the temples. Packed lunch, drinks, pick ups and drop offs, and all transport and tickets included in the very resonable price!