Tiger Sheep

Game bundles have been highly successful for several years at this point. Starting with the first popular bundle, Humble Indie Bundle, the burgeoning popularity of the pay-what-you-want structure is now commonplace.
 
For PC gamers, bundles are a great way to build up your game library and discover new (mostly indie) games without spending lots of money. It’s easy to gain twenty games for a mere ten bucks or so after a few bundle purchases. The beauty of bundles is that there is usually a charity aspect: buyers can choose the percentage they want to give to a charity organization, which could mean 100% of their purchase could go to a charity. Or 100% could go to the game developers, an option that’s not very prevalent when it comes to normal game purchases. Goodness knows game developers could use more direct purchases!
 
High spenders are often rewarded by getting their name displayed on the site next to the amount they paid for the bundle, so those who can spend full retail for all the games get a nod for their generosity. These spenders also make the bundles more monetarily successful.
 
Bundles are notorious for using Steam keys as the way to redeem purchases. Desura is also common, although the offerings are slim and tend to be lower quality or less popular games. However, it is nice to have a few alternatives to Steam, and a wider offering will likely create more customers, ultimately increasing the amount of money that goes to charities and developers.
 
My favorite game bundles these days are:
 
The Humble Bundle. No bundle list is complete without this forerunner. It’s expanded past selling mainly indie games to featuring larger developers, though it hasn’t forgotten its roots. The bundle also offers other types of media, including ebooks, movies, and graphic novels. Book bundles are becoming more and more popular and I’m hoping to see Humble really excel in that area.
 
Groupees started out as a music bundle service and is now one of my favorite game bundle services, mainly because of the variety they offer. One of the neatest things they do is the Build a Bundle, which allows you to choose the games you want from a choice of options at various price points. This means I don’t end up with duplicates, which is an issue with a lot of bundles, especially those which all seem to offer the same games as other bundles.
 
Another popular bundle, Indie Gala provides all of the traditional bundle features and has frequent offers. Their happy hour is a neat feature that reduces the price of gift purchases depending on certain factors.
 
If you want to look into more bundles on your own, the Indie Game Bundle Wiki is a great place to start.