Several, especially discovering how to melt wizard, various things with Killer, Daystar's accidental politeness-magic-works thing for Shiara, various other fairy tale parodies... but what takes the cake is Cimorene's choice of cause of death: Old age.
Searching for Dragons:
Willin tries to convince Mendanbar to marry a "proper" princess.
Mendanbar: Willin, you haven't been talking to that dreadful woman with all the daughters, have you? Because if you have I'll... I'll use you to test out that new rack you want so badly.
There's also the explanation of why the rack needs replacing to begin with: Mendanbar's great-great-grandmother had it removed to dry tablecloths on.
Mendanbar: She made someone haul a rack up eight flights of stairs and down six more, just to dry tablecloths?
Willin: A very determined woman, your great-great-grandmother.
Mendanbar's general hostility towards Willin at the beginning of Searching for Dragons.
Pretty much everything the gargoyle says. Its entire purpose in life seems to be just harassing Mendanbar.
Calling on Dragons:
Arona getting turned into an enormous blue winged donkey courtesy of all of Killer's many layered curses being transferred over to him as his punishment.
