More keen command-line stuff, pointed out to me by smart folks in the Mac conference on the Well: you can send man pages straight to your selected printer. For example, for a handy printed reference to the "open" command, type:

man -t open | lp

The "lp" command itself (part of the CUPS printing architecture in 10.2+) has all kinds of handy options, too -- for multiple copies, delayed printing, and so on. And now you know how to print the lp manpage...