This is a simple, rather charming ghost story.
In 1895, a grocer by the name of Thomas LeCount decided to move from the south side of Gardner Lake to the east side. Now, where as slackers such as you or I would decide to simply build or purchase a house in the new location, a go-getter such as Thomas LeCount figured that he already had the house he wanted, and he had the ambition necessary to simply move the house from one spot to the other. He figured it would be easy, as the lake was frozen, and....
...well, you probably have already figured out where this is going.
The two-story house was raised and placed on sleds. LeCount and company go about 300 feet onto the lake when the ice began to crack. After attempting to pull the house back, the moving crew decided to stop at nightfall and complete their work the next day. The problem is that the local mill drained some water out to use it to generate power, resulting in the ice no longer having water to rest on top of. The ice finished breaking, and the house pitched over into the water.
The house did remain in place until the spring thaw, until sinking into the lake, coming to rest on the bottom 15 feet below the surface.
The thing is, portions of the second story remained above the water line (come versions of the story claim that the house floated for several years which seems unlikely at best, but the second story and/or attic remaining above the waterline? That's actually pretty likely). The second story remained visible for years, and locals would fish off of it in the summers, and ice skate through it in winters. By 2005, the house had rotted away, and I suspect (though I cannot confirm) that the top floor was gone long before that.
But nobody died, and the situation was more comic than frightening. So, where does the ghost story come in?
Well, locals have long held that, at night, piano music could be heard coming from the lake. The house did, in fact, have a piano (as well as some other furniture) in it at the time that it sank. Allegedly, scuba divers in the lake have reported that portions of the house, including the piano, are still present underneath the water. And, on quiet nights, music can be heard coming from the spot on the lake where the house came to rest.
Commentary: First off, this is a delightful story. It is whimsical in a way that ghost stories so rarely are. That said, it is difficult to fathom the "ghost's" alleged origins - most ghost stories either have an origin as part of the story, or imply some sort of weird or dark doings that caused the place in question to be haunted. But not this one. It is just a rather odd and funny story about a house move gone bad, with ghostly music tacked on as almost an afterthought.
My guess - having the second story of a house peeking out from a lake is pretty odd, and it sounds as if it became a local landmark. That being the case, it seems likely that kids and local raconteurs began circulating the story in order to creep out each other or others. The house sticking up out of the water was probably sufficiently weird to give the story staying power, and now it's just part of the local lore.
Regardless, it's a fun story and I am glad that I encountered it.
Sources: iO9, Wikipedia, Damned Connecticut