Subject: How do you make brown from red, green, and blue light?

That is, in the sense that red + green gives yellow (or what we perceive to be 
yellow) and green + blue gives cyan, how do you make the color we perceive 
as "brown" out of red, green, and blue light? I know that the word "brown" 
covers a wide range of colors, but I'm talking specifically about the color 
produced by the "Brown" crayon in a Crayola set. Is there a way to mimic that 
color simply by combining (in various amounts) red, green, and blue photons? 
And if so (and it must be so, right?), what are those various amounts?

Re: How do you make brown from red, green, and blue light?