Vintage kids' LPs with built-in animations

Retrothing has a great article on Red Raven records, which came with the cells of an animation printed on the LP label. You put a mirrored circus tent-topper over the spindle and watched the animation in its surfaces. I had one of these when I was a kid and I absolutely loved it.

These were cardboard children's records with the animation printed right onto the disc itself (later versions like the one above had the animation on the label of regular colored vinyl). The Red Raven included a little mirrored device that you pop onto the turntable's spindle that reflected the animation in such a way that while the record plays you get to see a little cartoon.

The effect is rather hypnotic (the mirrored device is an ersatz praxinoscope for all of you optics junkies), and a neat addition to the typical children's fare on the record itself. Sixteen Magic Mirror Movie records were released by Red Raven (making for 32 animations of course).

Link (Thanks, Adzoum!)