I got some plumbing fixtures in the mail and the box was a great size for cats, so I put it under the bench by the front door (where I've noticed the boys sitting lately) and layered the bottom with an old towel. Sure enough, it was an instant hit.
I think the new location is preferred, since it's near a heat register. I know I keep the house temp low (I have to wear a fleece and/or hat a majority of the time) and this is how the cats compensate.
Sitting on me:
Sitting on each other:
Or sitting on the stove (the pilot light makes the metal warm):
They are soooooo cute.