I've been up to this fresh water lake north of Chiang Mai twice in the last week. Its set in outstanding mountain scenary with floating huts around the edge where you will be served very good Thai food and beer at around 200Baht/person.
Have a swim in the water, take a boat out, absorb the beautiful scenary, avoid the Farang Kee Nok for a day, see a pretty impressive Buddha (no temple), do a spot of birdwatching (there are some pretty impressive birds here such as the Crested Serpent Eagle).
A TukTuk will set you back 300-400Baht from the old town in Chiang Mai both ways (driver waits for you there). Alternatively, you can get a moped, its about a 25 minute ride, head towards the massive sports complex, 700 stadium I think, just after the stadium, 1km or so, you'll see a blue sign for Huay Tung Teo straight ahead, then 50m later, a sign to turn left, up the road, 20Baht entry/person.
