This episode marks the first appearance of Barney's apartment, The Fortress of Barnitude.
Barney's apartment features a clonetrooper, which only appears in the star wars prequels. In later episodes he bashes the prequels. The clonetrooper is in later episodes replaced with a stormtrooper from the original trilogy.
When Marshall is talking about Mamma Mia, he states that "won all sorts of Tony's and stuff". Although it was nominated for 5, Mamma Mia did not win a single Tony award.
Lily says she always wanted to slap Barney but she did in the season 1 finale and blamed it on the universe
Valerie Azlynn (who plays Barney's one night stand) played Veronica on iCarly, a girl who was only attracted to Spencer because he wore a tux, this girl says she's in love with Barney who always wears suits.