A video from Nate McCoy documenting the making of a MIDIBox SID.
The MIDIBox SID is a DIY synthesizer, based off of the MOS Technology SID sound chip, the 8-bit sound source of the Commodore 64 computer.
More information on the MIDIBox SID:

http://www.ucapps.de/
http://forum.midibox.org/
http://www.midibox.org/dokuwiki/
http://www.avishowtech.com/mbhp/buy.html

Demo videos of the MIDIBox SID.

http://youtube.com/watch?v=lnTh4e0b-ic
http://youtube.com/watch?v=FrgdErwTJ5o

 
HyperSID is a donationware subtractive synthesizer with all the C64 SID chip hardware capabilities besides many new software based features - so you can take advange of various controlling features of a VSTi and also real analog sound with SID character.
HyperSID software is used to control a HyperSID synth - a DIY design based on the [...]

 

 Oxygene demo: Play Now | Play in Popup | Download

The MB-6582 is a four channel stereo synth (8x 6582 SIDs) diy project. More photos here.
Here’s a video of the MB-6582 in action:

Synth fans: Don’t watch this video of the MIDIbox SID Bassline unless you’re ready to lust after something that can’t be bought:

You can build one, though. The MIDIbox SID, based on the Commodore 64 sound chip, is a very cool DIY project.

Elektron has announced that it’s restarting production of the SidStation, a unique sound module based on the Commodore 64’s sound chip. The production run is limited to 100.
The new batch of SidStations is built exactly like the previous ones. All original parts have been hunted down to assure the original sound.
The SidStation is a MIDI-controlled [...]

What can you do with some worthless old computer equipment when you have too much time on your hands?
This site shows that you can do a lot, if the worthless old computer is a Commodore 64. Back in the days, the Commodore 64 was one of the first personal computers. They were popular before Apple [...]