the osi today announced the approval of two microsoft open source licenses, the Ms-PL (Microsoft Public License) and the Ms-RL (Microsoft Reciprocal License). the osi process is one that is in the open and allowed microsoft and open source communities to discuss the nature of the licenses in an open forum. as a result of that process, the licenses (after being renamed to the above) were approved. the licenses were submitted to the osi on 10 aug 2007.
this means that ironruby is officially an open source project :-)
UPDATE: you may have noticed the "public license" -- no that isn't a typo. this is what the community process suggested the permissive license be renamed to for osi approval...so permissive license == public license.
UPDATE2: (old) community license == (new) receiprocal license
you can read more about it here: osi approves microsoft license submissions.