Sharp Boom Box + Mini Organ - Don't Just Sing Along Anymore
I think that most people will agree that the 80's were the golden age of the boom box. Actually "silver age" would be more appropriate since the coolest and most collectible blasters are usually measured by how much chrome they're clad with. Amplitude and clarity were the most important features, but there are a few portable systems that tried to leap ahead of the pack with a little something extra.
The Sharp MR-990 is one of the rarer examples of a feature-laden 80's boom box. You've got AM & FM (no shortwave?), dual cassette, detachable stereo speakers, five-band EQ... but what's in that little drawer in the middle? Pop open the little hatch, and out slides the Sharp "Melody Computer" mini-organ. It has a couple different tones and rhythms, chord accompaniment - it looks like pretty typical Casio keyboard stuff, but the sound is coming out of your Sharp boom box.
There's a little sequencer inside as well as a lot of other little buttons that appear to be for step entering your song, maybe even a little editing. You can also play the keyboard in real time, but the sharps and flats require an extra keypress - so don't rely on this to replace your regular performing axe any time soon. The MR-990 is cool and very rare. I've linked to one that's on auction right now, but be prepared to bring your wallet. There were only ever a few models of boom box with a built-in keyboard, and this is one of the rarest.