Staying on a houseboat in Amsterdam is definitely a must-do experience. Had a wonderful time on Daan's boat, especially since the weather was so nice. Sitting on top of the boat, having a beer while watching the other boats go up and down the Amstel, was paradise.
We stayed with 2 couples in the 2 full bedrooms. The boat is like a mini-house, full bathroom kitchen etc. Great location on the Amstel, 3 mins from Centraal via the metro, 20 min walk to Leidseplein/museums.