I've had a lot of luck planting the roots of those live lettuces they sell with the roots attached, I've managed to get about 3 more heads depending upon how early I plant them.
The coolest thing I managed to do, after having read through this thread quite a bit, was I successfully managed to grow some winter wheat, red wheat, and rye. It took about 3 weeks to germinate, likely because of a cold snap that happened in the middle, but I couldn't believe the grains actually popped up some plants!