The best sport climbing area in the world. Probably.
I am not sure a lot more than that needs to be said. If you are after good quality sports climbing, Kalymnos has it all. Thousands of routes on over 50 different crags, and still potential for many more. The weather is near perfect in spring and autumn, and the routes are solid, clean, and very well bolted. The island still has very few cars (please hire a scooter rather than a car and keep it that way). The ambiance in the restaurants doesn't leave a lot to be desired.