A truly wonderful graphics interface that is taught in a very poor (ie nonexistant) fashion in 
LSD.  It does things like display windows and polygons in a very quick and easy manner (especially compared to Windows GDI stuff) and is generally fairly good at doing complex things.
-  Totally less awesome than the [SDL], though. --ChainMaille
-  SDL is good for most of the things you'll need in games, but when you're doing really fancy things with graphics, you need to revert to OpenGL anyway.