The Laundromat is a major location in Dr. Horrible's Sing-Along Blog, seen in Act I, II, and III. It is where Billy first saw Penny, where many
Penny at the Laundromat
of their conversations took place, and it is where Dr. Horrible's slide into evil began. It was where Penny's Song and parts of Brand New Day and So They Say are sung. Notably, a scene of Dr. Horrible and Penny dancing in the laundromat is also featured in the song My Freeze Ray.