RPG Maker is what it sounds like: a game engine for making RPGs. It has a good map editor and you can piece together good simple RPGs in a very quick time, you can also make rather complex and intricate games. The limit is your imagination, oh and it only runs on Windows.
Here’s a good tutorial on building a village and short game. It’s designed so you can try out most features RPG Maker has during the one month trial. You can also find this Tutorial Town on Steam.
GameMaker can be used for quick prototyping to finished and polished games. It’s a Windows-only game engine that has a good community behind and a lot of good resources online.
Here’s a good series of videos on getting to know GameMaker.
As always you can find a list of more game engines on the game creation software page.