I've never eaten turnips
The real answer: I can't think of one off the top of my head.
The morbid humor answer: Stephen Hawking.
You have three seconds to understand that one. xD
Broccoflower, Fiddleheads, Rutabaga, Celeriac, Watercress...and probably a whole lot more veggies that are grown around the world that aren't common here.
Avocados... if thats even a vegtable.. isnt it a fruit? Idk
More than a few.. One which as just sprung to mind is an Eggplant. Have you tried this at all?