We've done our fair share of grilling vegetables like asparagus, portobello mushrooms and the like. But watermelon? Does that even work? If Mark Bittman says so, we believe it. Have you tried grilled watermelon?True to form, Mark Bittman put together a stellar list of interesting vegetables to throw on the grill in today's New York Times. Sweet potatoes and jicama? Come to think of it, those sound great grilled. And I could go for a tasty marinated slice of grilled eggplant. But lettuce? And watermelon?! Who knew?