Bruce Norris’ Pulitzer-winning play does what good plays should by dragging secrets, emotions and hidden assumptions into the harsh light of day.

The play’s two acts take place, respectively, in 1959 and 2009, in the same house. In Act One, members of a white Chicago neighborhood respond to the news that a black family is moving in. Act Two finds a white couple planning to move into the neighborhood, now all black. (Here’s Ted Hoover’s review for CP.)

What Norris does especially well (and as ably communicated in this excellent production) is show how racism has shape-shifted as society changes — and how even the sort of people who might be his audience are implicated.

It’s easy to laugh, for instance, at the bald prejudice of a nerdy white 1950s real-estate salesman. (And whatever else it is, Clybourne Park is a very funny play.) But the laughter sticks in our throats when a confrontation over gentrification reveals that contemporary white thirtysomething yuppies have their own racial issues.

These are folks, for instance, who don’t understand why saying you once dated a black person is offensive to African Americans. Nor why your dating history isn’t even proof you’re not racist. Nor why, for that matter, having an African-American president doesn’t make us a post-racial society.

Ran across an interesting article in Slate about the media/social-media phenomenon of Charles Ramsey, the Cleveland guy who was a hero in the rescue of three captive women recently freed there.

Ramsey fully deserves praise. But writer Aisha Harris points out that his celebrity is part of a disturbing trend highlighting working-class African Americans whose manner and speech conform to a certain preconception, or make them entertaining in a certain way.

It’s an insidious kind of racism that disguises itself as tribute. And it’s the sort playwright Norris is so good at pinpointing.

Clybourne Park runs through May 19. Tickets are $15-55.