The JRuby team has just announced the release of JRuby 0.9.2 (download). Despite being a minor point release, a lot of things have been tweaked and added. Direct from the team:

This release has some great improvements:

Extensions openssl and readline now working
Code for a new graphical irb console
Partial support for iconv and bigdecimal extensions
RSpec now supported
Improved Rails support
Fixed all known block and scoping bugs
Enhanced parser performance
More compiler and performance work
Refactored variable scoping logic
127 Jira issues resolved since 0.9.1

Congratulations to the JRuby team for their continuing efforts!