YoYo Games offers a free game development tool called Game Maker 8.
Game Maker 8 enables users to develop simple video games using a drag
and drop editor. Game Maker 8 gives users the ability to customize
backgrounds and actions throughout their games. For the first-time user
YoYo Games offers a series of free Game Maker 8 tutorials.

Game Maker 8 is
available in three versions; Studio which will allow you to export games for play on PC or Mac, Standard
which for $50 unlocks advanced features and supports Windows 8, and a Pro version which costs $100 and unlocks even more features and supports mobile play.

YoYo Games hosts hundreds of relatively simple online games created by amateur and professional game developers that you can play for free too.

Applications for Education
Game Maker 8 could be a
good tool for students to use to try to develop educational games.
After a unit of study instead of having kids give a presentation have
them try to develop a game which demonstrates what they’ve learned.
Perhaps they could develop a game based on a set of mathematics concepts
or a game based on a set of historical events.