I just love yoga, I chose to do it once a week on Tuesdays.
According to most calendars, that's the 3rd day of the week, with the week starting on Sunday.  But I think many of us see it as the 2nd day of the week.
I think so too, nowadays week usually starts on Monday. And Yoga is so relaxing, perfect for beginning of the week.
It seems that yoga originated in ancient India - do you practice a certain type?
I like Bikram yoga myself. I think there is many different kinds. I heard of Ashtanga yoga as well.
Do you do the Bikram yoga where they add the heat and humidity and is then known as hot yoga?
Yeah that's what I like about it. 
I'm not so sure I'd like that - exercise under hot and humid conditions - sounds like a good way to make myself pass out - LOL!
You do need a lot of endurance to do it, but if you like exercising it's perfect for you. I like yoga because different poses challenge my body.
There is actually a classical Hindu yoga text written in the Sanskrit language - it describes the 8 components of yoga.  I bet that's an interesting read!