Colorize text matching a regex through a pipe?

[gcmarx-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Gordon Marx)]

On Wed, Dec 29, 2010 at 11:52 AM, David Kramer <david-8uUts6sDVDvs2Lz0fTdYFQ at public.gmane.org> wrote:
> Is there a linux tool that can work as a pipe (read stdin, write to stdout) and colorize any text
> matching an regex? ?If not, I'll have to write one. ?Not that hard, but I would hate to reinvent
> it.

If it's the last thing in your pipe, grep --color works great, but
somehow I sense that's not what you're asking for. What's your desired
output format?

Gordon