Agile is trendy in project management since the day it came to the world (refer to Agile keeps rock the PM world). With PMBOK 6 Edition incorporated Agile concepts, you should not miss this project management methodology.
The most classic cartoon about agile is probable the Pig and Chicken one. The pig and the chicken are going to open a restaurant. The chicken would like to name the restaurant Ham and Eggs, which caused the pig refused the proposal, as the pig believed that he would be committed and the chicken is just involved. Although it is a funny cartoon, it reveals the commitment issue in a team. Pigs and chicken should commit as a team. If pigs realize that it is not possible to deliver what they committed to, they should have a conversation with the chicken. You know that I am talking about the development team and the product owner, right?
Such interesting agile cartoons can be found on Agile Safari with deep thoughts on the problem below the scene. Check the reference for more interesting sites about agile.