There are a number of literary, historical and pop culture references in the Baldur's Gate series. For example:
Marlowe and Vongoethe from ToB are a reference to Christopher Marlowe (author of Dr. Faustus) and Johann Wolfgang von Goethe (a German who later wrote Faust). Both works tell the story of a man who sold his soul to the devil for wealth and power. If you know who Marlowe and Vongoethe are in ToB that makes sense.
Cyrando from the Temple District could be inspired by Cyrano de Bergerac.
Jan Jansen may be a nod to this infinitely recursive rhyme which appears in Vonnegut's Slaughterhouse 5:
My name is Yon Yonson,
I work in Wisconsin,
I work in a lumbermill there.
The people I meet when I walk down the street,
They say, "What's your name?"
And I say,
"My name is Yon Yonson,
I work in Wisconsin..."
It fits because Jan Jansen pretty much never shuts the hell up.
Xzar says "I am become death, destroyer of worlds." This is something J. Robert Oppenheimer said in an interview about atomic bomb testing. He was quoting the Bhagavad Gita, a Hindu religious text where this line was spoken by the god Vishnu.
"Oh Captain, my Captain" (spoken by the Spectator Beholder in ToB) is the title of a poem by Walt Whitman. [edited...I wrote play before because sleep deprivation.]
The moose and squirrel in a cage in Waukeen's Promenade in Athkatla must be a reference to Rocky and Bullwinkle.
Anyone else know of others?