Which religion has worship Friday or on Satuday mornings?

The only religion I am familiar with that does this officially is Judaism. The Sabbath, their holy day starts at sundown Friday night and runs until sundown Saturday night.

However, there are a variety of religions, including Christianity, that hold services at other times during the week (the LDS for instance, or the 7th day adventists hold theirs on saturdays). I have seen many christian churches offer Friday or Saturday night services, and even some in the middle of the week.