My star week is ovulation, that's when I gain most water (also I get super-hungry just before it).
I don't mention mine at all though. I feel silly saying 'star week' - would rather just say 'hormones' or 'period' (or 'time of the month' for ovulation) which is more adult. But because everyone else says star week, I would feel like I was going to gross everyone out if I said anything else!