I live in a small Southern town where a lot of people still enjoy the fine art of canning their own foods. My best friend and her grandmother picked wild blackberries this summer and made jam that my kids can't get enough of. We finished up one jar and had to beg for another! I can't think of a better (or healthier) way to dress up an average PB&J.
My aunt used to make plum jelly that makes my mouth water just to think about. Note to self - I need to try to make some next year!
If you're not in the canning business and don't know anyone who is, check with your local farmer's market, flea markets, local grocers, etc. A lot of people make jams/jellies/preserves and sell them. You will definitely appreciate the variety of flavors, freshness/quality of the produce used, and the extra love that goes into homemade products.