Yay! There's not so long left to wait now! Sorry for no answering fo SOO long.
You mean 'favourite' episode? As of Gumball - I don't really know. There were many nice and funny episodes. Well, one of the most memorable episodes for me is when Penny lost her shell. As of Star - there are really no 'best' episodes for me. Almost all of them are equally good, except the ones that depict solely Ludo's life.