Ah, the mixtape. One of the most sentimental gifts of the 20th century, with the added benefit of telling someone who you were through your musical choices before the days of Facebook.  MakerBot has come up with a delightful way of reviving the mixtape: a 3D printed MP3 player kit that looks like an old-fashioned cassette. You can either download and print the chassis yourself with the 3D Replicator and assemble the device, or order the whole gadget in assembled form. The Makerbot Mixtape holds 2GB of music, can be used as a USB stick, and plays directly through a headphone jack.