First there was the 1982 Seiko TV Watch...but quite bulky with the seperate tv tuner that needed to be attached to the watch.
Then the NHJ VTV-101 watch with the built in VHF/UHF tv tuner:
Now there's a couple on the market (or coming soon) with internal memory to play videos, mp3s, voice record and even an FM radio. They appear to be redesigns of those Nano knock offs all over ebay (amv/mtv movie format etc).
The former isn't on the market quite yet but there's a review of the latter here