This year's cool summer has been great for growing rhubarb, a versatile plant that is taking a starring role this week at the Grand Rapids Farmers' Market. The idea came Patti and Arnold Schmidt from Schmidt Family Farm . Arnie and Patti are known for growing monster rhubarb, and they've challenged other farmers, gardeners and market customers to a "biggest rhubarb leaf" contest. The whole market has joined in. This week vendors are offering rhubarb-based baked goods, crumbles, crisps, brats,