David Letterman enjoys being yelled at by Billy Eichner

Being yelled at never looked so fun.

Comedian Billy Eichner ("Parks and Recreation," "Billy on the Street") stopped by the "Late Show with David Letterman" on Thursday night and played a rousing (and loud!) game of "Celebrity Child or Kentucky Derby Winner?" with the host.

The game was simple: Letterman had to guess if each name belonged to a celebrity's child or a prize-winning horse. (With names like Bluebell Madonna and Moxie Crimefighter, it's not as easy as it sounds.)

Letterman was so delighted by the game -- and Eichner's mile-a-minute signature yelling -- that he asked to keep playing even after the initial 30 seconds were up.

One more note on Eichner -- Vulture notes that before one of Joan Rivers' appearances on the "Late Show," the late comedienne urged producers to have Eichner on as a guest. Something tells us she'd be proud.