For reasons I don't understand, Baumbach directed Highball under the name Ernie Fusco, and credited the script to Jesse Carter. In fact, the only credit he took in the production was for a birthday song that appears at various points in the film, including the credits, with the amazingly creative lyrics, "Everybody Felix/It's Felix's Birthday!".
The movie is split into three parts, each being a different dinner party. Most of the characters appear in all three parties, separated over a few month period. There really is very little to say about the plot, it's delightfully absent for the first part. For example, Felix, probably the funniest character in the film, is inexplicably comatose in the final party, and the characters only hint at his condition. For some reason, this makes the entire scene that much more amusing.
This movie simply has one of the funnier scripts I've ever seen. By eschewing any basic elements of plot and story, the film instead focuses on the characters' interactions with each other, which always end in laughs. Highly recommended for someone in need of a good, silly comedy.