Open GL:

 Vertex
 Color
 LoadIdentity
 PushMatrix/PopMatrix
 Translate, Scale Rotate
 Begin, End
 PostRedisplay
 LookAt
 Ortho
 Perspective
 Enable, Disable
 Depth
 Fog
 Light

Concepts / behind the scenes:
Depth Buffer, Color Buffer
Depth Test / Z-buffer algorithm vs Painter's algorithm
Lighting Mathematics: 
   specular, diffuse, ambient
Collision Detection - sphere-sphere intersections