If you're exhausted from gambling at one of the many casinos, then grab a taxi and head over to Macau Tower, a refreshingly non-gambling-related attraction. I went on a Friday afternoon and things were pretty quiet. Once you got your ticket and made it upstairs, you are greeted by great views over Macau from 300something meters up. Walk on the glass floor or, if you feel really adventurous, take a skywalk or bungee jump, although both aren't exactly cheap. Time-wise, about an hour will be plenty.