Salty, old PC gamers remember Westwood Studios for many reasons, but it's mostly for Dune 2. Yes, this is also the same studio that created Command & Conquer, but its RTS predecessor that was responsible for establishing many of the genre's core conventions is the one based on Frank Herbert's fascinating sci-fi universe.
This '90s RTS is a topic of conversation today because it is now playable right in your browser. That's right: you can play Dune 2 in its entirety right now at play-dune.com (via Kotaku). The HTML5 app runs smoothly in your browser, though my iPad didn't want to make nice with it. It appears to be an imperfect port, with missing or slightly altered features and balance, but don't forget that it's entirely free.