“I am not crazy, my mother had me tested�
IQ 187
Sheldon entered in college at the age of 11, graduated Summa Cum Laude at the age of 14 and got his first doctorate at the age of 16!
Most of his t-shirts are related to the comic universe. He usually wears t-shirts about DC Comics characters.
Soft Kitty is a song that Sheldon's mother used to sing to him when he was sick as a child. Today, he still requests his caretaker to sing this song to him whenever he falls ill. Sometimes he also sings to others who have fallen ill.
Sheldon has claimed to be an honorary graduate of Starfleet Academy, and is an avid fan of science officer Spock (Star Trek).
Sheldon is in love with Amy Farrah Fowler, a neurobiologist. By Sheldon's own admission, she is most like him by any standard.
He always wear a long sleeve shirt under his t-shirts.
Bazinga is a word used by Sheldon to signal that what he said immediately before this utterance was to be taken as a joke. Sheldon's ability to surprise and irritate people with jokes is rooted by his inability to recognize sarcasm and his inability to recognize when he is being too harsh in certain social situations.
Source: bigbangtheorywikia.com