Sir

Q : Where does Sir Ian McKellen go to party?

A : A knight club.

イアン・マッケランはイギリスの俳優で、ナイトの称号をもらっているので、ナイトクラブのnightとknightを掛けています。

　　　　　　　　　　　　　こりゃいつの時代のナイトだか、、、

Sir Ian McKellen was knighted in 1991 for his services to the theatre, and the joke playfully connects this honor with the concept of a "knight club," infusing the punchline with wit and levity.