The first party which Henry (Kevin Kline) takes Louis (Paul Dano) to takes place in a Manhattan Art Museum named "Neue Galerie New York," which means literally "New Gallery New York," and which specializes exclusively in 20th Century Austrian and German art and decorative art. When Meredith (Celia Weston) mentions that someone is "over by the Klimt," the reference is to a painting called "Adele Bloch-Bauer I," seen on screen prominently, which was painted by Gustave Klimt in 1907.
The wedding scene at the end of the film, and the rice throwing on the street afterward, took place at The New Middle Collegiate Church, Second Avenue, East Village, located between Sixth and Seventh Streets.
As Henry drives Louis and himself to the theater for the first time, Henry demonstrates that he is a wild driver, without concern for other drivers and pedestrians. At one point, a voice off-screen yells "Asshole!" This is what Otto would exclaim from time to time as he wildly drove through London in A Fish Called Wanda (1988). Both Henry and Otto are played by Kevin Kline.
Louis's car was a 1974 Pontiac Grand Ville 2 door, which was the last full-size convertible built by Pontiac. Pontiac Grand Ville was the top-trim model in Pontiac's full-sized line from 1971 to 1975. It replaced Pontiac Bonneville, which had been Pontiac's top-trim model since 1958.