looks like a lemon, tastes like an orange!

This here's a yuzu, a citrus fruit cultivated in Japan and around East Asia. On the outside it looks like a small grapefruit, with uneven skin, and is usually bright yellow or lime green. Our local green grocer cut one up while we were shopping at his little market this afternoon for our usual strawberries, bananas and apples, and after some coaxing (the boys expected it to taste sour like a lemon) we each tried a wedge. It was so sweet and juicy we bought a whole bunch to take home. To read about yuzu in Japanese cuisine, check out this wikipedia article.