Jason Koebler, writing for Vice, has another good high-level explanation of just what the hell is going on:
What is going on is that GameStop, a company that sells physical
copies of video games next to Auntie Anne’s pretzel shops in dying
malls, is the most highly traded asset in the United States, a
“meme stock,” and currently the primary front in a micro class
war. GameStop’s stock price jumped from $4 last summer to $20 at
the end of 2020, to $40 two weeks ago. It was worth $100-ish at
times on Monday and Tuesday, and as I write this it is worth close
to $300. Essentially, many normal-ish people have made a huge bet
against gigantic financial institutions and are currently winning.
In practice this means we are seeing one of the largest wealth
transfers from the financial ruling class to the middle and
middle-upper classes in recent memory, so it is, understandably,
the only thing anyone is talking about.