Flipsiders were a series of games disguised as audio cassettes. With a flip of the wrist the game board would slide out of the bottom and unfold. The magnetic game pieces were stored in a compartment at the top of the cassette, and there was a spring-loaded switch which when pulled back and released would spin two gears in the place of the tape reels. Those gears had numbers on them and were used in place of dice. I had a few Flipsiders, but my favorite was Dragon Master.