What are tropes, you ask? "Tropes are devices and conventions that a writer can reasonably rely on as being present in the audience members' minds and expectations." They're similar to cliches, but without the negative connotation. (Although if you've read this post, you know that well done cliches are A-OK with me) I found this video through a link on one of the pages (I can't remember which one, I spent hours there the other day) and it illustrates tropes far better, and funnier, than I could describe them.
That was awesome right? Anyhow, the site breaks down tons of plot devices and other writing tidbits with really funny, easy to understand descriptions. There are also examples of each one, in several types of media.
A few of my favorites: (Be forewarned - This site is addictive!)