These are some of GT characters best memorable and funniest moments that comes to mind. Please add your own favorite moments from the show :)

James: The funniest moment I remember him best is in the episode "The Nude" where JJ is trying to paint portrait of girl in bikini. The way James Hold his stomach in trying to look cool, and standing next to JJ as he paint the girl is so hilarious.
https://i.ytimg.com/vi/iDTEy86fxfI/hqdefault.jpg

Florida: In "Florida's Night Out" episode, at the end where she come home late from the date, she put JJ and Thelma in their place who criticizing her to being late and not calling. And she dance to her bed room as she sing "I could have danced all night". What a performance.
https://i.ytimg.com/vi/n1vxuNBCmGw/hqdefault.jpg

JJ: Most memorable scene from JJ was when gave a speech in honor of Alderman Davis. He was suppose to say good things about Davis, but changed his mind midway speech and went on say how crooked Davis was.
https://img.sharetv.com/shows/episodes/standard/228603.jpg

Willona: In the episode "Willona, The Other Woman", Willona invite Bookman to her apartment to find out where Bookman spend his nights away from home, and accidently pour coffee on Bookmans pants.
https://img.sharetv.com/shows/episodes/standard/228641.jpg

Thelma: When Thelma first met Keith, she invite him for diner cooking him a home made meal. The whole gang ganged up on her as Keith was trying to cut the steak.
https://ionetheurbandaily.files.wordpress.com/2015/04/14294610570099.jpg

Michael: In the episode "Where there's smoke", he imagined himself being Casanova and JJ's girlfriend going crazy over him.
https://i.ytimg.com/vi/kOCQYHVgMgg/hqdefault.jpg

Bookman: In the episode the "Rent Party", he got on stage and imitate Howard Cosell. He bust out laughing during his dialog :D
https://i.ytimg.com/vi/HrDyP4PeHB4/hqdefault.jpg