known

# MRI Rubies
[ruby-]1.8.6[-p420]
[ruby-]1.8.6-head
[ruby-]1.8.7[-p352]
[ruby-]1.8.7-head
[ruby-]1.9.1-p378
[ruby-]1.9.1[-p431]
[ruby-]1.9.1-head
[ruby-]1.9.2-p180
[ruby-]1.9.2[-p290]
[ruby-]1.9.2-head
[ruby-]1.9.3-preview1
[ruby-]1.9.3[-rc1]
[ruby-]1.9.3-head
ruby-head

# GoRuby
goruby

# JRuby
jruby-1.2.0
jruby-1.3.1
jruby-1.4.0
jruby-1.6.1
jruby-1.6.2
jruby-1.6.3
jruby[-1.6.4]
jruby-head

# Rubinius
rbx-1.0.1
rbx-1.1.1
rbx-1.2.3
rbx-1.2.4
rbx[-head]
rbx-2.0.0pre

# Ruby Enterprise Edition
ree-1.8.6
ree[-1.8.7][-2011.03]
ree-1.8.6-head
ree-1.8.7-head

# Kiji
kiji

# MagLev
maglev[-26852]
maglev-head

# Mac OS X Snow Leopard Only
macruby[-0.10]
macruby-nightly
macruby-head

# IronRuby -- Not implemented yet.
ironruby-0.9.3
ironruby-1.0-rc2
ironruby-head