one for the (record) book(s)
A remarkable, unusual, and unexpected event, occurrence, or piece of news. Mr. Literature Snob reading a trashy romance novel? Now that's one 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, there's one for the record books!"
one for the (record) books
An outstanding, memorable, or record-breaking event or achievement. Wow, you finished a 32-ounce steak in less than five minutes? That's one for the record books! You should have seen your faces when Dad popped out of the bushes to scare you! Boy, that was one for the books.