Most of the very best games on the PC need you to cough up at least a little cash, but if you absolutely must game for nothing, then let us show you how it's done.
If you look past the obvious avenues for playing on a PC - massively-multiplayer games like World of Warcraft (that require a subscription fee) or digital shopfronts like Steam - you'll find there are countless games that are free in some form or other that are often as good (and sometimes even better) than their paid equivalents.
We of course can't list all of the really great free PC games. We could spend all day just talking about the great flash games over on Newgrounds, for example. But for a nice smorgasbord of free gaming content, from downloadable to browser-based titles, this should have your weekend (or week, or month, or year!) covered.
Genre: Third-Person Shooter
It's Like A Free Version Of...: Battlefield
I've had a love-hate relationship with this game for over a year now. I love the gorgeous cartoon graphics and casual-friendly game mechanics (instant deaths are very rare), but the game's insistence on constantly spending money to maintain good equipment and weapons means that those who want to plat for free and be the best in the game will run into problems.
Extras: You can buy basically everything in this game, from fancy new uniforms for your characters to power-ups to bigger and better weapons.
Developer: id Software
Genre: First-Person Shooter
It's Like A Free Version Of...: Quake III
Quake Live is basically classic multiplayer shooter Quake III, only now instead of having to buy a copy you can play it in a browser window and you can play it for free. Simple!
Extras: There's a premium subscriber model for Quake Live, which lets you start and manage your own private games.
Developer: Iron Helmet Games
Genre: Space Strategy
It's Like A Free Version Of...: Master Of Orion
Neptune's Pride began as a labour of love for a handful of ex-Irrational Games developers, and through word-of-mouth has blossomed into quite the cult hit amongst fans of space strategy sims like Master of Orion.
Extras: You can buy bigger galaxies to play in, more stable matches and bigger games with the purchase of in-game credits.
Genre: World Building/Survival Horror
It's Like A Free Version Of...: Well, Minecraft
The undisputed indie smash of 2010, Minecraft drops the player off on a deserted island and forces them to fend for themselves, building a shelter from the surrounding terrain and then moving on to battle monsters, dig for gems and...build enormous statues of Final Fantasy characters.
Extras: There are two versions of Minecraft, free and alpha, and while the alpha (ie paid) version will give you access to what's basically a singleplayer campaign, the free version - which only has the world-building stuff - is still a blast.
Developer: Tarn Adams
Genre: World Building/RPG
It's Like A Free Version Of...: There's really not much like it.
Before Minecraft came along and stole its thunder with its fancy 3D graphics, Dwarf Fortress was the PC gaming world's best kept secret. You play as a dwarf, and can either go off on an RPG-like quest or can build yourself a settlement.
Extras: Nothing, it's completely and entirely free. Those who simply cannot stomach the game's primitive graphics should grab Stonesense, though, as it turns the 2D ASCII art into more pleasant isometric 3D terrain.
Developer: Semi Secret Software
It's Like A Free Version Of...: Prince of Persia, if the Prince never stopped running and was under attack by an unstoppable alien invasion force.
In Canabalt, you press one button - to jump - and that's it. You'll have to press it a lot, though, because it's the only way you'll outrun a city that's collapsing around you under the weight of an alien invasion.
Extras: It's a flash game, so as long as you're playing it on your PC or Mac, it's free. No catch. If you want to get it for your iPhone, though, that'll cost you.
Genre: Massively-Multiplayer Online Role-Playing Game
It's Like A Free Version Of...: World Of Warcraft
Lord of the Rings Online is one of the best MMOs around that wasn't made by Blizzard, and in a welcome move, has recently announced a shift to a "free to play" model. Like other games on this list like Battlefield Heroes, this means you'll be able to sign up, create a character and play without ever paying a cent. Hey, Bilbo never had to cough up to travel Middle Earth, why should you!
Extras: You're of course handicapped if you go the free-to-play route; those parting with cash will receive all kinds of bonuses. But hey, you're playing a time-consuming MMO for free, you can suck it up and deal with it.
We've barely scratched the surface of what's possible on the PC (and in many cases Mac) when you want to game and want to do it for free. So now it's your turn: what are your favourite free games?