Speaking of breaking the rules... here's a device that has become way overused, but it's loads of fun anyways: Lensbaby (selective focus.) The lensbaby is low tech, it doesn't send any information to the camera at all, it's basically an aperture on a shifting bellows, allowing you to set the "sweet spot" to somewhere other than dead center. There's no autofocus, so if you have rotten vision like I do, it can be difficult to get it right. "Live view" helps.
It does make for some fun shots though (if you can ignore the horrifying chromatic aberration, HA!).Dong Ding IDong Ding II
(Does anyone else start singing "Dong Ding the witch is dead, Which old witch? The Wicked Witch...?" as soon as you start brewing this tea? I know I know! Batsh*t, huh?)