Leslie Winkle solves a problem Sheldon had been struggling with by changing the equations on his whiteboard.

Lost the Physics Bowl by blowing the final question and refusing to allow his teammate to provide the correct answer.

Misidentified a cricket, thus losing a rare comic book to Wolowitz.

A paper he delivered to Stephen Hawking had a mathematical error on the second page. Hawking called it "quite a boner."

Sheldon believed that he had figured out how to synthesize a new stable super-heavy element but in the end it's revealed that he confused square centimeters with square meters.

He thought that Tweetie Bird taught he taw a Romulan.

Believes a Van Dyke is a goatee without a mustache.