CV/gate interfaces are groovy.

I've got one of those Radio Shack Moog things, and (ten or fifteen years ago) I used to have an el cheapo Korg drum machine (now deceased) that had a trigger jack in the back, so it could trigger the Radio Shack thing. Naturally the Korg didn't know from pitch, but it was still fun because I could hold down keys for pitch. Instant Kraftwerk a là "Endless Europe": Just add cheapo analog delay pedal!

I suppose the whole techno thing with old analog gear has to do with the fact that it's a hell of a lot more fun to push crappy equipment past its limits than it is to dial up a preset and fall asleep. This is why people get so fascinated with guitars: It doesn't just do what you tell it to. It's got a personality and an agenda of its own.