Raj suggests "the actress who played TV's Blossom" for their physics bowl team to replace Sheldon. That actress, Mayim Bialik, does have a Ph.D. in neuroscience. Bialik joined the show in the Season 3 finale and became a regular cast member in Season 4 as Dr. Amy Farrah Fowler. Raj also says, "How about the girl from 'The Wonder Years'?" He is referring to Danica McKellar, who has a degree in mathematics, coauthored a physics theorem, and appears in the Season 3 episode The Psychic Vortex (2010) as Abby. Coincidentally, in The Wonder Years (1988), her character's last name is Cooper.
Queen's "We Are the Champions" plays during Howard(Simon Helberg)'s triumphant moment at the 29th Annual Physics Bowl. Fittingly, the lead guitarist for that song, Brian May, is an astrophysicist.
The Bat Jar cookie jar that Leonard gets Sheldon is now a highly prized collectible.
The scene from Star Trek (2009) that Howard describes depicting Spock's birth was indeed filmed, but was eventually cut from the final movie, although it was later included as a deleted scene on the home video version.
Penny asks a question about The Brady Bunch (1969). Years prior Kaley Cuoco played oldest sister Marcia in Barry Williams' TV adaptation of Growing Up Brady (2000).