Sometimes Sober Saturday
A Sometimes Sober Saturday is a Saturday that qualifies as being sober. This can be for any reason. It is really more of an event, than an adjective.
Joe: "Man, last night was boring, I had a sometimes sober Saturday. :("
Tim: "I've got a lot of homework, I think I'm going to participate in a sometimes sober Saturday."
Tim: "I've got a lot of homework, I think I'm going to participate in a sometimes sober Saturday."