The ruby-1.9.1 had come to the world, and
several days went by...
and I have worked for making the merb to be correspond to the ruby-1.9.1.
And now we are very happy, because we can announce there is the first child of Merb and ruby-1.9.1.
http://merbi.st is the site which is running on merb with ruby-1.9.1.
Our efforts are remaining at several places.
Most of them are in github
Others are published on here http://merbi.st/plugins