Jason Segel not only plays the piano and sings "You Just Got Slapped", but he also composed the song. He has performed in several of his projects including "The Muppets" (2011) and "I Love You, Man" (2009). Perhaps most famously, he wrote and performed the music for the Dracula musical in "Forgetting Sarah Marshall" (2008).
First time the apartment's piano is played.
This episode introduces the recurring gag of both Ted and Robin hearing a phrase or word that resembles a military rank, (eg. "I have this kernel stuck in my teeth"), then proceeding to salute and repeat what was said, as though addressing a military officer ("Colonel Stuckinmyteeth").
Younger Bob (Eben Ham) makes an appearance in the spinoff "How I Met Your Father" (E6) as an angry neighbor.
In the flashback when Barney attempts to celebrate Halloween a day early, he is impersonating Borat, a character invented by English comedian Sacha Baron Cohen.