1) The characters of Ted, Marshall, and Lily are based on the show's creators, Carter Bays and Craig Thomas, and Thomas's college sweetheart and wife, Rebecca.

2) Unlike most multi-camera sitcoms, How I Met Your Mother shot episodes over a span of three days as opposed to just one.

3) Another difference was they actually filmed in a silent studio. The laugh track was added in later when they would screen the episode for an audience.

4) Barney's character was originally described as a "Jack Black, John Belushi type," but as soon as Neil Patrick Harris auditioned for the role, the creators got rid of the description.

5) During his audition, Neil Patrick Harris acted out Barney playing laser tag. He did crazy dives and rolls, even slamming into the creators' desk and knocking everything over.