Probably the biggest example is in the second film, where a bunch of cowboys and ninjas randomly burst into Finletter's Pizza shop and fight, only to be shooed away by George Clooney about a minute later.
As mentioned, a young George Clooney appears in the second film, in the role of the heros horndog best friend. In one scene, he is found running a fake "Win a date with Rob Lowe" contest to trick attractive young women into going out with him. Naturally, this scene is now hysterically funny for a dozen reasons nobody involved could have imagined.
In another scene the director stops the movie to announce they're out of money until George (seated away from the rest of the cast near some hot girls) casually suggests they do product placement to make up the difference. The whole thing oddly predicts George's rise to leading-man heartthrob fame while the actor playing the hero gets no respect.
Intended Audience Reaction: Yes, they couldn't possibly have made a movie this bad without doing it on purpose. And then they did it again and...
Misaimed Hatedom: It seems that the majority of the people who hate the film think that killer tomatoes are too stupid an idea to take seriously, not understanding that it's not a serious film.