Photon printer, a 3D printable laser engraver build using DVD drives by Isolt:
This is an entry for the Light It Up contest on the grounds that a laser diode is a specialised form on light emitting diode.
The Photon Printer started out as a quick weekend project then quickly escalated when I saw that there was room for improvement in the current designs. The design turned out to be quite fun and I really enjoyed seeing it work at the end.
DIY pocket laser engraver – [Link]