|OS:||Windows, Linux, OS X|
Stella is an open source, multi-platform Atari 2600 emulator.
Some may say that emulating an Atari has no point, since the games were so simplistic due to hardware limitations of the time that gaming has far surpassed them. However, if you have a curiosity for Atari despite not being born in the era, or if you just want to re-live some nostalgic memories, this emulator is great. It also has some television filters to up the nostalgia factor.
SDL 2.0. You need this as it's required to run Stella (and some versions aren't packaged with it.) It's easy to install. It's just a .dll that you drop into your Stella folder.