The 5823 Noise Sorcerer is an amazingly fun (if not always predictable) noise source. Great for hi-hat sounds; just run it though an LPG and you're golden! Adds a lovely haze to raw waveforms run through it. Can do weird things when you hold a magnet up to it. Different behaviors between 5823A and various makes of 5823/Z900T tubes.
And dat plasma glow!
Also the Voltage Controlled Annihilator! Nasty pulse distortion/waveshaper from which you can coax a very unstable suboctave. (I've also found you can get it to behave more like a regular VCA by running audio to the CV in and vice-versa but why would you want to do a thing like that?
) Here's a track in which I get some subtle use out of it in order to restore attack transients to audio coming from a Montreal Assembly Goodbye24, which is a very lo-fi pitch/delay effect.
http://soundcloud.com/everyonediesscreaming/tangles
