what do you know!
(well) what do you know
A phrase used to indicate one's surprise upon discovering something. Hey, what do you know—we have chocolate chips in the cabinet after all. Well, what do you know! It says here that my ancestors first came to this country in 1857!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
(Well,) what do you know!
Inf. a way of expressing surprise at finding something that is unexpected; an expression of mild surprise at something someone has said. (No answer is expected or desired.) Andy: Well, what do you know! Here's a brand new shirt in this old trunk. Bob: I wonder how it got there. Tom: These two things fit together like this. John: Well, what do you know!
See also: what
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.