I think these custom printed M&M's are worth mentioning. Admittedly, the only DIY part is choosing the color and adding the message, but that's more power over a candy than I've ever had before and frankly, I think it is very cool.

You could propose, break-up (okay, that would be bad), congratulate, thank, do just about anything that can fit on the back of an M&M. With a huge variety of packaging options and a decent color selection you can make it fit any occasion. I'm sure they will be a hit as wedding favors or shower favors. What fun messages would you dream up?