Here are some popular game creation tools that I have heard mentioned recently:
There are tons more.
As far as I know... Construct Classic is free and is for making 2D windows games. Construct 2 is the new one by the same people and is html 5 for cross-platform development. Game Maker Studio is either free or paid for depending on what features you want and how cross-platform you want your game to be. FlashPunk is for making flash games... which is kind of cross-platform but in a short-term way. And the Unity Engine is a free 3D engine that a lot of things seem to be saying they are using recently.
(I don't really know, I am just making notes from what I heard!)
Edit: one more: Monogame - it's an open source port of the XNA framework for true cross platform compatibility.
