The most spectacular event imaginable in the universe.
Preceded by if/when/unless to
represent the sort of circumstances under which you might
change your mind about
something.
Girl 1: Are you coming to Josh's party tonight?
Girl 2: Meh, I gots to
work tomorrow. But call me when you're there if Angelina Jolie turns gay with Megan
Fox.
**Later that night**
Girl 1: Hey! They just found Osama bin Laden hiding in Josh's basement!!
Girl 2: Dude, I'm sleeping. I said to call me if Angelina Jolie turned gay with Megan
Fox.