Someone watching from the sidelines started filming a neighborly conversation between the two, which terminated – most excellently, to borrow a phrase from Bill & Ted – when Pitt went inside, grabbed a beer and lobbed it to McConaughey.
Because he's Matthew McConaughey, he popped it open and drank it.
Other relevant details: The beer in question was a NOLA Hopitoulas, according to bestofneworleans.com, and McConaughey's in town with New Orleans Saints quarterback Drew Brees to film a segment for The Amazing Race. (Pitt and Angelina Jolie own a home in New Orleans.)
Bonus Rumor Mill Grist: Pitt has been one of the names floated around as a possible lead for True Detective's second season. Should that be true, here's hoping he gets to play a character with as great a name as "Rustin Cohle," McConaughey's character in the show's first season.