For those that dont know, the Raspberry Pi is a $35 computer on a self contained board with a Broadcom SoC with a 700 MHz ARM 1176JZF-S processor, 256 MB of RAM, Ethernet connection, dual USB ports and a SD card slot.
It has sold in bucket loads, with a healthy waiting list just beginning to clear. Applications for the Raspberry Pi are legion and this one is the first I've seen that turns it into a synth.
The UK based modder in question who remains enigmatically known as Raspberry Pi Synthesizer on Blogspot has built a single OSC synth in software. You can see the results of his ongoing experiments on his dedicated blog.