Project page: nilsimsa RubyForge project page.

Wiki: nilsimsa wiki

From cmeclax's page:

A nilsimsa code is something like a hash, but unlike hashes, a small 
change in the message results in a small change in the nilsimsa code. 
Such a function is called a locality-sensitive hash. 

Martin Pirker (mpirker) is responsible for the port, but Jonathan Wilkins (jwilkins) is the new maintainer so bug him with problems.