How about that!

how about that(, then)

Used to indicate that one finds something to be very interesting, exciting, surprising, or respectable. Said as an exclamation, rather than a question. A: "I heard Janet is running for a seat in the Senate." B: "Wow, how about that!" Well, how about that—the government actually passed a tax bill that the majority of Americans support!
See also: how

How about that!

Isn't that surprising! A: My husband and I just celebrated our sixtieth anniversary. B: How about that!
See also: how