Count me in with the Holga fans!
I got into a rut with my usual 6x7 and 6x17 b+w transparencies, and the pursuit of a certain type of technical excellence.
So I junked my rule book, picked up a couple of Holgas and and a Brownie Hawkeye, reversed the lens and had great fun with all 3. Helped free me from my self-imposed visual shackles, taught me a lot about how creativity works and can be challenged, and made me look at the world with different eyes.
Have printed some of the resulting pictures as polymer photogravures...