Leonard Nimoy

Sheldon is obsessed with Leonard Nimoy, who played Spock in Star Trek

Nimoy has taken a restraining order out on Sheldon.

Penny got a napkin signed by Leonard Nimoy when he visited the Cheesecake Factory and when Sheldon found out that it had a stain from Nimoy, he was excited because he had his DNA and could make Leonard Nimoy clones.