The TV show Family Guy very often, usually multiple times per episode, will cut away from the main plot to show a weird flashback or just a miniature story that is completely unrelated to the main plot even when it's framed as having been a flashback. Family Guy isn't the only show/movie that does things like this it just seems to be the one that does it the most often.
Now, I don't know where I picked the term up from, but for the longest time, I've been referring to these asides as mise-en-scenes. But I'd just recently looked up a bunch of different definitions for that word, and it doesn't seem to quite fit. (edit: it seems this section is confusing people. I'm not asking what mise-en-scene means, I'm asking what the word for the thing I've described in the first paragraph is)
But then, what is the proper term for these?