Best resources for learning CG?

I’ve been trying to do a crash course in Cg programming, but I’m having trouble finding approachable documentation. Many docs seem to require a prior understanding of graphics programming, or include quite a bit of engine-specific code. What are the best resources for an intermediate programmer to get up to speed?

Have you read the Cg Tutorial? If not, read the whole thing.

Yes, though I’ve had trouble wrapping my head around it. I’ll read through it again. Some short tutorials or well-commented shader source would be incredibly helpful.