For example i just picked up a machine for dirt cheap that everybody seems to have forgotten about that sounds like nothing else i've ever used.
![Image](http://erikhall.mine.nu/~ronny/drum/rx5.jpg)
Yamaha RX-5
It's a 12 channel 12 bit drum machine from 1985. It's comepletely archaic to use the internal sequencer but if you couple it up with other midi signals running to it you can trick it into making some weird sounds. All the sounds from it are really in your face, probably due to it being a 12 bit machine. All the drum sounds have amp envelopes which is peretty weird for something from '85.
or this:
![Image](http://www.synthony.com/vintage/vintage.images/poly800.jpg)
Korg Poly 800
It doesn't look like much but this board makes some Battlestar Gallactica weird alien outerspace sounds. I've played with some new Korg stuff that has sounds from this peice but none of them seems to nail it dead on. These are still cheap and solid. There are some new mods you can buy or have installed for these that do some sweet sh!t. There's one that gives it some Moog style filters and another one that gives it 2 extra oscillators that are both sick as fck.
What else have you guys run across?