I knew one therapist (a friend) who worked on Saturdays while she was getting established in her practice. She eventually gave up Saturdays though. My own therapist doesn't work weekends, and I haven't heard of any who work on Sundays. I know it's not uncommon to work into the evenings on weeknights though if you were trying to find someone to see you after work. I also hear some of them see clients pretty early in the morning during the week so some can go before work.

Sid