In Sheldon's incredibly short trip to the Grand Canyon at the end, the music accompanying him is the interlude "Flight of the Bumblebee" from the opera "The Tale of Tsar Saltan" by Nikolai Rimsky-Korsakov.
"Our friend the beaver" was the title of Zonker Harris's college-level biology term paper in the comic strip Doonesbury.
At the end of the episode, when Sheldon runs to the Grand Canyon, the song playing is The Flight of the Bumblebee " which is the theme song of another hero, The Green Hornet (1966).
In the TV series Charmed (1998), Battle of the Hexes (2005) Kaley Cuoco's character (Billie) ends up putting on a war belt that belonged to Hippolyta granting her Wonder Woman like super powers. Hippolyta is the mother of Princess Diana (Wonder Woman) in the DC comics series.