The Boxing Episode: Urkel and Fuffner use boxing to resolve their dispute over the right to date Laura.
Bring It: Subverted, when Fuffner is about to land the knockout blow to beat Urkel once and for all. Three boys in the crowd, all whom also have their eyes on Laura, decide they've had enough of Fuffner and, in turn, challenge Fuffner, to which he (foolishly) says, "I'll take you all on!" Then about 20 other boys in the crowd call his bluff, and Fuffner and Waldo decides to take the hint.
Reasonable Authority Figure: The school's gym coach, realizing that Urkel and Fuffner will probably still fight each other even if he brings them to the principal's office, gets them to agree to settle their dispute with a proper boxing match where they will be fully supervised and have safety equipment to prevent serious injury.