You'll find a vast number of Slashcode work-alikes. The basic idea behind /. has been cloned many times. Debian stable includes "squishdot", a Zope-based CMS that works similarly to /. But I'd recommend taking a trip over to http://www.opensourcecms.com/ and/or http://www.cmsmatrix.org/ and taking a look. You'll find many alternatives, complete with feature comparisons, reviews, and demos.