Well in that case *copy paste*
Here are some links. Some of these have short learning curve while other demands that the user knows C++ etc.
- AGS - Engine for making 3rd person point and click adventures like Monkey Island.
- RPG Maker 2000 - Engine for creating simple (Final Fantasy clones?) RPGs.
- RPG Maker 2003 - Engine for creating more advanced RPGs than RPG Maker 2000.
- Ianout - Engine for making Fallout clones
- IrrAdventure - Engine for making Myst clones
- OGRE - 3D graphics and physics library suitable for RPGs, adventures etc.
- ErisMUD - A MUD engine
- J.U.R.P.E - A dungeon crawler engine
- Worldforge - Engine for 3D games.
- Panda3D - Another 3D engine (claims to have a short learning curve)
- OpenGL - A great 3D graphics library
- SDL - A multimedia library
- ZClassic - Engine/Editor for making Zelda clones
There are probably a lot more of them out there, but this is a start. I haven't tried any of them out. Some of them are still being developed and will probably be of much more use to most in due time. Judging by the screenshots I'd have to say that OGRE looks real good. And of course SDL and OpenGL are already used among the developers
