DokuWiki is a nice and simple wiki that is relatively easy to install in your Redbrick account/webspace. To make things more interesting, you can integrate the login (and template) with your Wordpress blog software (if you use it on Redbrick).
You just need to follow the normal instructions to install it. You can then configure it, as per the DokuWiki instructions anyway you like.
Unlike Wordpress, DokuWiki has built in support for running behind a proxy. To enable the proxy, you need to configure it in 'conf/local.php' with these lines:
$conf['proxy']['host'] = "proxy.dcu.ie";
$conf['proxy']['port'] = "8080";