I recall once upon a time seeing a pretty interesting mug that changed from a dressed girl to less dressed girl at /r/. After looking around some, I've discovered they are referred to as morphing or heat sensitive mugs. But I haven't found anyone that seems to be selling any sexy ones. Is this the kind of item you need to have custom made? (Saw plenty of those sites) And if so, any recommendations on how to make a good one? I don't want one that is just plain black and then becomes an image.

Something more like this:
http://www.youtube.com/watch?v=LnnjT6NrEuo

And I'm also interested in what other fun items people at /jp/ have come across. Because there seem to be a lot of things that pass by unnoticed while we focus on PCV models, dolls and VNs. I had for example no idea there were hawaii shirts with clever anime prints making it look like a normal one at a distance.