When Barney is talking to Ted through the ear piece he says "Iceman to Neruda". Iceman and Neruda were the code names they were using while picking up girls using the play book. Barney's code name being " Iceman" is a reference to Val Kilmers character in the 1986 movie "Top Gun". Ted's code name was Neruda, which is a reference to Ted's favorite poet "Pablo Neruda" which he talks about in season 4, episode 9 "The Naked Man".
Ted refuses to pay for stamps, but earlier in the series Barney gave Ted a lifetime supply of stamps to keep Ted and Robin from fighting.
In the elevator, Barney (Neil Patrick Harris) dresses up in a beard, sailor hat and pipe. In the Netflix series A Series of Unfortunate Events Neil Patrick Harris' character Count Olaf wears a disguise that is very similar.
Marshall and Strickland discuss the Teenage Mutant Ninja Turtles. Abby Elliott who appears as Jeanette in this episode, later appeared in Teenage Mutant Ninja Turtles (2014). And Taran Killam who portrays Gary Blauman in other episodes, also appeared in that movie.
The intro to this episode and the title is a reference to the movie Weekend At Bernie's