recenlty after updating rubygems Istarted getting a lot of warning like this when running ruby or executable gems:

NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299@global/specifications/rake-0.8.7.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/bundler-1.0.12.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/bundler-1.0.7.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/heroku-1.12.0.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/heroku-2.0.4.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/httparty-0.5.2.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/httparty-0.7.7.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/json-1.4.6.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01. Gem::Specification#default_executable= called from /Users/morgy/.rvm/gems/ruby-1.8.7-p299/specifications/json-1.5.1.gemspec:10. NOTE: Gem::Specification#default_executable= is deprecated with no replacement. It will be removed on or after 2011-10-01.

Using RVM the fix is to run

 rvm rubygems current