Version 0.4.0 of Neo4j.rb came with improved traversal performance, more options on how to use relationships, for instance relationships can now be indexed. Version 0.4.1 gave us migrations and access to a batch inserter for big import-once data volumes.
In the last days of 2009, neo4jr-simple was first released. It's a simple ready to go wrapper for Neo4j and currently in version 0.2.1. Make sure to check out the neo4jr-social example application as well!