Double Plumsey
Two of something rare in a row (either good or bad).
A: "Did you see that guy who got stuck by lightning two days in a row?"
B: "Poor guy, a lightning double plumsey is bad luck."

A: "I was playing poker last night and I got a full house."
B: "Nice."
A: "Yeah, and then I got another full house straight after!"
B: "No way?! Double plumsey."