I made a Kosmo Sloth Chaos (KAOS?) using a PCB from NLC:
Of course it would’ve been easy to draw up my own PCB and have it made, or to do it on stripboard. But the board was only $8 and I wanted Andrew to get paid for his creative efforts.
How useful is it? I haven’t had it long enough to figure that out really. It’s fun, though. Its usefulness is no doubt strongly dependent on the kind of music you’re making. It’s designed for slowly evolving ambient stuff, but the fastest version I think could be more generally applicable than that, used to vary say a filter and a VC envelope generator on a lead.