The Null Device
The Optigan was apparently a toy musical instrument sold by Mattel in the early 1970s; it used analogue optical discs (similar to film soundtracks) to store recorded instrument sounds which it then played back (which makes it something like a toy Mellotron or somesuch); which sounds like it'd tie in with the casiopunk/retro-kitsch/chip-music/indie-synthpop memes. Now some geeks have put up a page dedicated to this instrument. There's even a band called Optiganally Yours who appear to be from Seattle or the SF Bay Area or somewhere like that and feature this instrument in their performances; they have a track on that Human League tribute compilation which Stephin Merritt is overrepresented on.
And if you want the Optigan sounds but don't have one, you can buy the official Optigan sample CD, for a low US$199. (I think I'll pass; especially since they're just samples which, as the page says, don't sound like the real thing when played. If they provided them in a VSTi plugin which emulated the hardware's idiosyncracies, sort of like the M-Tron Mellotron softsynth, it'd be a better deal. Mind you, I believe I paid less for M-Tron than these people are asking.)