I go to Saturday morning meetings. I'm really starting to wish I could make it to a meeting during the week, though, as I end up eating too much on Saturdays after my meeting thinking "Oh, I have a week to work this off!" Silly me.
There aren't weigh-in threads for different days of the week. Some of the sub-forums have WI threads - the Momentum/Flex area has a monthly WI thread, and I think there is a Thursday thread floating around somewhere. Feel free to start one if you're looking for people who WI on the same day as you