I make dandelion jelly every spring...tastes like honey. If I can get to enough of them at the right time, I also make violet jelly. It tastes a lot like the generic 'mixed berry' or 'wild berry' filling in pop tarts and other storebought treats. I never make very much, maybe 6-10 half-cup jars of each kind. Just enough to keep a few for us and give the rest out as novelty treats.
I also want to try rose petal, lilac, and peony, it's just a matter of remembering I want to make them when they're in bloom.