So crazy that it needs it's own thread. You really never see stuff like this, ever.
From the movie "Tokyo!" which is a collection of 3 short films. Comes out on DVD the 30th I believe.
I don't have a lot of info on this short but from the bits shown in the trailer here
her transformation doesn't seem to be one way. In fact it appears she can do this at will at some point as you see her running around naked for a moment in the trailer and ducking to hide by a bus stop to TF again before someone sees her naked. I imagine she performs this trick a few times on the way home to avoid being caught nude on the street.
I plan to pick this DVD up as soon as I am able and to rip the TF bits out so that they may be shared.
edit: After some checking I've found the short is titled "Interior Design" and that the girl does indeed gain the ability to change between human and chair at will.
edit2: Notice: This youtube link is no longer valid. Uploaded clip can be found
here instead.