Now this is naturally going to include a lot of comedies but is certainly not limited to comedic movies. Looking for movies in any genre where if you were to try to take the watch all the way through without laughing, the chances of failing are as close to 100 % as humanly possible.

It could be due to simply a single scene in a movie that it makes it impossible to keep a straight face or the kind of movie that just in one scene after another has so many such moments that the chances of getting through all of them with a straight face approach zero. It could in theory be pure, unadulterated slapstick, brilliant, Mark Twain level social satire and/or anything in between. Anything to make you fail the try to watch without laughing challenge.