Customize Tool Tip Display

I'd like to be able to change the overall appearance of the tool tips globally. 
(perhaps font, bg color, size, etc)
For that matter I should ask, are there presently any ways? Not counting making mouse overs, I mean.

(perhaps font, bg color, size, etc)
For that matter I should ask, are there presently any ways? Not counting making mouse overs, I mean.
