(MICO Is CORBA)
A CORBA ORB for C++, distributed under GPL.
It's pretty good at what it does - though I remember that earlier it had severe problems with compilation requirements (compiling old GNOME with no X running and 32 megs of memory and small swap space was just plain impossible). I hope it has improved (a lot of blame went to gcc, which wasn't that optimal with C++ at the time...)
MICO was used in GNOME, until they developed an ORB of their own (ORBit). MICO is being now used in KDE and a lot of other C++-based open source projects.
Home page: http://www.mico.org/