frazzled - To feel completely exhausted and worn out, and unable to think straight, after a great deal of mental or physical effort
After being up two nights in a row writing a 60 page history paper, and drinking 60 cups of coffee, Simon's mind felt frazzled.
scintillating - Describing someone or something that is exceptionally witty and entertaining, and is intellectually or emotinally stimulating.

Her scintillating conversation captivated those she talked to at the dinner party, leaving them laughing and enjoying themseles.