Just to share a little project I spent some time on.
People around their 40s (like myself) may like it!
Its a full Atari 2600 Emulator written in Java from scratch, with no libs used. Just pure Java.
It can be used online and supports some network multiplayer, which is something that Atari emulators never had before.http://javatari.org
You have to find your own ROMs though.
But it is very easy to use, you can just drag and drop any file or link directly from the browser into the emulator window and it will automatically load it.
You need Java on your machine.