The Change-Up (2011)

Great watch, would watch again, and can recommend.
This is probably my favorite "body swap" trope movie. It's Ryan Reynolds and Jason Bateman for crying out loud. If you've ever liked anything they've ever done (aside from "Green Lantern") then you'll probably like this. Seeing them do "impressions" of each other is a bonus.
As far as "body swapping" goes, I think this is the only non-parent child, non-male female swap that I've seen, which is probably what makes it a lot of fun: there's no socio-political debate sitting in the background on single vs married, but all the fun of "now I have to deal with THIS". Maybe there are some issues of how redeemable the characters are in their flaw sets, but it's built into the premise.
With Leslie Mann and Olivia Wilde backing up the leads, everyone gives a stellar performance. The production value is clearly there, though I think most of it went into locations and cast budgets: this isn't an action-car-chase movie, it's a "body swap" dirt humor rom com.
The writing does skew dirty in the humor, but if you have an open mind, then the humor ends up being in the surprise of dealing with each others lives unprepared. Despite the juvenile basis of guys trying to do whatever they want, the movie is surprisingly touching and about togetherness.