Have you ever been in a position where you needed a quick break but your players were too ancy to break as well?
When dealing with nobility and court settings, players can sometimes skip the roleplay aspect and jump straight to behavior such as, "I bow, greet all in the court, and ask the duke for his assistance." While in most scenarios this type of action is sufficient, taking it a step further can enhance gameplay (or maybe even manipulate a plotline).
A new substance is found in an out of the way area and kept very quiet. It is found to make a perfect counterfeit diamond. Only the most expert of expert appraisers would even have a hope of noticing that it is fake. Only one problem: if it gets wet it starts to slime and if it is saturated, it turns into a glob of gel.