Chris,

It's unlikely that your webhost will let you install a newer version
of mod_ruby, as the Apache configuration is usually done per-server,
rather than per-client. Aside from that, though, you should be able to
configure and build a new ruby install anywhere inside your home
directory tree. Just use the
'--prefix=/home/<yourusername>/<someinstalldir>' argument to the
configure script, make, and make install (without doing an su to
root).

You will have to update the #! line in your CGI scripts to point to
your Ruby interpreter instead of the system one, but after that, you
should have it.

Alternately, if you really want the 1.8 functionality inside mod_ruby,
you should take a look at the 'shim' library, which provides the bits
that were added in 1.8 to a 1.6.X installation as an extension.

Hope that helps,

Lennon