[XeTeX] How may I get colored background on text?

[Ron Aaron]

Hello, all --

I am a happy user of xetex (plain), but one thing I am having
considerable difficulty with is getting specific text to have a
different background.  For example, coloring rows of a table or anything
similar.

I cannot figure out what "\special"s I might need to accomplish this
rather mundane task -- any help would be most appreciated!

Thank you,
Ron