The wikipedia based website explains and gives examples of various things that TV, movies, and video games do, and gives examples of such things. The simplest example is the Red Shirt, which is someone on a show meant to die, usually to show something is dangerous. It is based on the original Star Trek (I thought this was universal knowledge, but apparently no one I know knew either about the trope, or about the name). It also explains the fourth wall, mooks, lampshade hanging, and various other things. The best way to see all this is to just start perusing the site
Just as a fair warning, it may Ruin your life

