I'm not really a fan of the whole chiptunes genre, but this review and guide to the Wayfar NES midi cartridge is intriguing. For about a hundred bucks, it lets you run a $5 NES as if it were a synth module with five channels. That's pretty cheap, and it sounds good in a retro kind of way. In this day and age of cheap four-octave keyboards, you could probably have a portable synth setup for less than $500. Tempting.
But a few questions, really: Why isn't there an SNES version of this, with its superior FM chip? What would this be like with a wind controller? Does blowing on the cartridge count? And why can't I get an NES-on-a-chip that'll do the same thing for $25 or so?