1st idea: "Machinima"
(From Wikipedia)
Machinima (a portmanteau word for machine cinema or machine animation) is both a collection of associated production techniques and a film genre (film created by such production techniques).
http://en.wikipedia.org/wiki/Machinima
It just hit me that it would be cool to have an episode devoted to Machinima.
Of course, Machinima has been popular in videogames, such as Halo (Red vs. Blue), The Sims 2 (The Strangerhood), Quake, World of Warcraft, City of Heroes, The Movies and yes, even Second Life =)
And another example of Machinima is MTV's Video Mods.
Check out the Wikipedia URL, above for LOTS of more info and links.
Here are a couple of other Machinima info sites, if you're interested:
http://www.machinima.com/
http://www.machinima.org/machinima-faq.html