http://tramadol.tfres.net/wiki/Main_Page has managed to evade the block. Their site is working again. Also, it appears that they use several different subdomains (e.g. http://soma.tfres.net/wiki/Main_page) which work as well.
Finally, there is another site that is even trying to copy the URL. http://en.wikipedia.ifc.com.pl/wiki/Main_Page