Usability 
Hotel search and booking service. Many listings for Western Europe and China but relatively few for the US and Japan. Nice menu driven UI. Results sortable by price star rating or "distance to central station". The site is German but has the option for English listings (some German words creep into the English pages but English-only readers should be able to understand.) You can request a booking, the hotel will call you back on your mobile if a room is available.