Perhaps my favorite (and most fruitful) gardening adventure is with French Breakfast Radishes. There was a packet of these in my clearance seed packet, and I'm glad, or else I may have never tried them, in lieu of swiss chard, kale, and fancier things. I sprouted them in empty eggshells (I read about doing this in a blog), and grew them on my windowsill (it was late February in Seattle - too cold to start these outside).
I picked them ~40 days later, and they were so adorable! I read online that they're ready when they pop out of the soil. I sliced them and ate them on buttered bread with sea salt. They were really tasty, and (the best part) some of the easiest vegetables I've ever grown.
Here they are! Keep in my mind my hands are pretty small, so they're only 3-4 inches long.
Forgot to add, I also planted a few of the starts outside (to see how they would do) in mid-June. I sort of let them go... because I wanted to collect the seeds! And it was success. At first they look like normal radish greens, but as they bolted they got to be ~ 3 feet tall! They flowered, and then the seed packets looked perfect for picking. And I chose to pick them right away, not after they dried for a bit, because I had to move. Anyway - I've collected the seeds and I'm excited to plant some more radishes next year. I love collecting seeds!