Trivia: In the fifth episode of the first season, Donna is left alone to babysit her little sister Tina. Both Tina and Valerie, Donna's older sister, were written off the show, much the same way as Richie's older brother Chuck, on Happy Days, or Laura's younger sister Judy, on Family Matters.
Trivia: During Bob's 'open for business' daydream, the man who has his hand up cupped over his ear while he says, "Now, if you'll excuse me, I'm next," is Gary Owens, who played the Announcer on the 60s-70s TV show 'Rowan and Martin's Laugh-In' and always had his hand cupped over his ear. In a few other episodes we only hear his very distinct voice.
Chosen answer: Danny Masterson is the one who screams "hello Wisconsin".