Some projects I've worked on:
http://www.opendylan.org/
http://docbrown.rubyforge.org/
http://treetop.rubyforge.org/
http://alexandria.rubyforge.org/
http://tanzanite.rubyforge.org/
http://apt.rubyforge.org/
http://xapian.org/
http://scooter.rubyforge.org/
http://rubyunix.rubyforge.org/