I've got a Nikon D200 (a bit older of a prosumer camera) on indefinite loan from my sis, who's ditched it for a Sony NEX-6.
She tossed this doodad in the bag, along with various aperture hole attachments.
It really needs a tripod, because it's a bitch to focus (hence the camera was literally sitting on the kitchen table for this shot), and only works in manual exposure, but it's really cool. Basically does the tilt-shift deal.
I really need to get a Manfrotto or something decent.
I considered buying one for a short while, but then I figured I'd probably use it once or twice, then never again. The drop-in aperture thing looks like a pain in the bunghole, too. So I didn't go for it.
If you've got a strong constitution and a brass ring-piece, you could always try free-lensing: Freelensing - Wikipedia, the free encyclopedia. Basically, pop the lens off, hold it near the mount and tilt it.