Last week (in the beginning of May) a couple of developers successfully ported Virtualbox for FreeBSD. This is substantial because there isn't currently any proper virtualization software for FreeBSD, so within the FreeBSD community - this is deemed even bigger than the porting of ZFS to FreeBSD. 
The Virtualbox people has made a nice draft on how to port Virtualbox, if you feel inspired to look at the procedure.
The original announcement-mail to the Virtualbox developer mailliste can be found here.
