Just before they leave for the maple syrup road trip, Christy says that she is going "breaking bad", a reference to Breaking Bad (2008). Matt Jones, who plays Christy's former husband, Baxter, starred in the show.
Chuck Lorre must have really liked the parking garage scene. Just four months prior a very similar scene played out in The Helium Insufficiency (2015) - except in Big Bang Theory it was helium instead of maple syrup.