A tiny, hole-in-the-wall place on Madison that doesn't accept credit cards and has a maximum occupancy of about 10 people. I'm not terribly familiar with authentic Thai cuisine, but of the various restaurants around Cleveland, Thai Kitchen had by far the most distinctive dishes and flavors. Whereas most places have a standard offering of flavors (you could go to any restaurant, anywhere, and have a similar dish), Thai Kitchen's menu has greater depth of flavor than the competition. The seasonings are my favorite of Cleveland's Thai restaurants, and the food comes on a scale of zero to 'Thai' (10). I had mine prepared as a 5 and it had plenty of kick!
The only downsides are the limited seating (as I said, fewer than a dozen seats) and the longer time required to make dishes from a smaller kitchen (45 minute wait for a group of 6). Overall, definitely worth a try!