Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
I have chosen a tricky title. Online games are available for anyone using a modern browser, be they Windows, Linux, Mac, BSD, or Solaris users. All that is required is either a Flash Player or the Java plugin, so if you have those, you can start enjoying online games instantly.
Still, good games are hard to find. Type in "free games" into a search engine box and you'll get tens of millions of entries, each offering great, free games. The problem is, there can only be so many great games. And which sites should you go to? How do you separate high-quality content from spam, promotion and trickstery? Which sites are safe for children? What about privacy and safety? Eventually, you will settle down for a handful of sites, but the quest can be long and tedious.