I've always loved the Lensbaby line of selective-focus lenses for digital SLR cameras (think tilt-shift in a tiny package), and the addition of the Optic Swap system in 2008 brought even more creative options to change the look of your images. But the one annoying thing about them has always been the fiddly process of changing the aperture of the lenses. You have to swap out various fixed aperture disks -- either by using the easily misplaced magnetic "aperture tool," or turning your camera face down and letting the disk fall out (often dropping it etc.). But the new Sweet 35 optic includes an internal 12-blade adjustable aperture. Compatible with the Muse, Composer (my fave), Control Freak, and recently released non-tilting Scout lenses, the Sweet 35 optic offers a 35mm focal length and full aperture stops from f/2.5 to f/22.
The Sweet 35 optic is available on the lensbaby.com site now for $180, though the company claims it's so popular that it's on backorder and will take a week or two from your order date to actually ship out.