I've been trying for some time to come up with a mod for the cassette tape. Initially I thought it would be cool if I could stick a voice recorder into one of those tiny cassette tapes that used to be used in message machines (trying to ironic!) but it was way too small.
Then I hit upon using one as an MP3 player. Surprisingly, no-one has completed one yet as an 'ible so I decided to go down this path. The hardest part was trying to find the right MP3 to be able to mod. I finally found this
MP3 Player on Ebay which fits really well into a cassette tape once the insides are removed.
The only changes you'll have to do is a bit of trimming to the cassette tape with a dremmel, a little bit of soldering and some design work and your done.
So in the name of irony, I present to you this Cassette Tape MP3 Player.