I usually remember the color wheel from physics classes as Roy G. Biv.
Somewhere in the mists of time I forgot that the complementary colors can be expressed as a bit of stock market advice, but remembered when reading Seth Kenlon on color correction in Final Cut Express:
and General Motors
"...which means that Blue is opposite of Yellow, so subtracting blue will yield yellow (while, obviously, adding blue will make a picture more blue. Red is opposite Cyan, so subtracting red will yield more Cyan, and finally Green is opposite Magenta and so to subtract green will make your picture more magenta."