that's a turn-up for the book(s)
That is a remarkable, unusual, and unexpected event, occurrence, or piece of news. Primarily heard in UK, Australia. Mr Literature Snob reading a trashy romance novel? Now that's a turn-up for the books! A: "After the concert, I ran into the singer at a pub down the road from the venue. It turns out his mother went to the same school as mine!" B: "Wow, that's a turn-up for the book!"