As Android phones have increased in popularity the number of apps available for the platform has rocketed.
And that means more free Android games. There's a lot of junk out there, but fortunately, there are gems within the junk.
We've worked our way through a whole load of Android games to reveal the ones you should download to your phone.
If we've missed your favourite free Android game, let us know in the comments.
1. Angry Birds
The amazingly popular iOS game moved to Android recently, earning over two million downloads during its first weekend of availability.
The Android version is free, unlike the Apple release, with maker Rovio opting to stick a few adverts on it rather than charge an upfront fee. The result is a massive and very challenging physics puzzler that's incredibly polished and professional. For free. It defies all the laws of modern retail.
Angry Birds for Android was first available to download from app store GetJar but is now available through Android Market.
Your standard gem-shuffling thing, only presented in a professional style you wouldn't be surprised to see running on something featuring a Nintendo badge with an asking price of £19.99.
You only drop gems on other gems to nuke larger groups of the same colour, but with ever-tightening demands for score combos and scenes that require you to rotate your phone to flip the play field on its head, Bebbled soon morphs into an incredibly complex challenge.
3. The Red Stone
There's an awful lot of square-shuffling games on Android and Red Stone is one of the best. And one of the hardest. You start off with a big fat 'King' square that's four times of the normal 'pawn' squares, then set about shuffling things so the fat King can get through to an exit at the top of the screen.
It's hard to accurately describe a puzzle game in the written word, but seriously, it's a good game.
Released a few months back in beta form, Newton is a maths/physics challenge that has you lining up shots at a target - but having to contend with the laws of nature, in the form of pushers, pullers, benders (no laughing), mirrors and traps, all deflecting your shot from its target.
The developer is still adding levels to it at the moment, so one day Newton might be finished and might cost money. But for now it's free and a great indie creation.
5. Sketch Online
Surprisingly free of crude representations of the male genitalia, Sketch Online is a sociable guessing game where users do little drawings then battle to correctly guess what's being drawn first. It's like Mavis Beacon for the Bebo generation. The version labelled "Beta" is free, and if you like it there's the option to pay for an ad-free copy.
Some might call Drop a game, others might classify it as a tech demo that illustrates the accuracy of the Android platform's accelerometer, thanks to how playing it simply involves tilting your phone while making a little bouncy ball falls between gaps in the platforms. Either way it'll amuse you for a while and inform you of the accuracy of your accelerometer - a win-win situation.
7. Frozen Bubble
Another key theme of the independent Android gaming scene is (ports of) clones of popular titles. Like Frozen Bubble, which is based around the ancient and many-times-copied concept of firing gems up a screen to make little groups of similarly coloured clusters. That's what you do. You've probably done it a million times before, so if it's your thing get this downloaded.
8. Replica Island
An extremely polished platform game that pulls off the shock result of being very playable on an Android trackball. The heavy momentum of the character means you're only switching direction with the ball or d-pad, letting you whizz about the levels with ease. Then there's jumping, bottom-bouncing, collecting and all the other usual platform formalities.
9. Gem Miner
You are a sort of mole character that likes to dig things out of the ground. But that's not important. The game itself has you micro-managing the raw materials you find, upgrading your digging powers and buying bigger and better tools and maps. Looks great, plays well on Android's limited button array. Go on, suck the very life out of the planet.
Another coloured-square-based puzzle game, only this has you joining them up. Link red to red, then blue to blue - then see if you've left a pathway through to link yellow to yellow. You probably haven't, so delete it all and try again.
A brilliantly simple concept. ConnecToo used to be a paid-for game, but was recently switched to an ad-supported model - meaning it now costs you £0.00.
Once you're successfully rewired your brain's 25 years of playing Tetris in a certain way with certain buttons and got used to tapping the screen to rotate your blocks, it's... Tetris.
It hinges on how much you enjoy placing things with your phone's trackball or pad. If you're good at it, it's a superb Tetris clone. Let's hope it doesn't get sued out of existence.
Not the best-looking game you'll ever play, with its shabby brown backgrounds and rudimentary text making it look like something you'd find running on a PC in the year 1985. But it's good.
You draw lines to box in moving spheres, gaining points for cordoning off chunks of the screen. That sounds rubbish, so please invest two minutes of your time having a go on it so you don't think we're talking nonsense.
Coloured gems again, and this time your job is to switch pairs to make larger groups which then disappear. That might also sound quite familiar. The good thing about Jewels is its size and presentation, managing to look professional while packing in more levels than should really be given away for free.
We had to put one Sudoku game in here, so we'll go with OpenSudoku - which lives up to its open tag thanks to letting users install packs of new puzzles generated by Sudoku makers. It's entirely possible you could use this to play new Sudoku puzzles for the rest of your life, if that's not too terrifying a thought.
A sweet little platform jumping game, presented in a similarly quirky and hand-drawn style as the super-fashionable Doodle Jump. You can't argue with cute cows and penguins with parachutes, or a game that's easy to play with one hand thanks to its super accessible accelerometer controls.