You can send a bug report or a feature request by filling an issue on the tracker∞.

Alternatively, you can subscribe to the rubycocoa-talk∞ mailing list and send your feedback or questions there.

If you have some feedback for the RubyCocoa developers, like a patch for instance, it may be better to drop it on the rubycocoa-devel∞ mailing list.

There is also an IRC channel at your disposal on the freenode network∞, called #ruby-osx. But not all the people could be there during your visit, so sending a message to either one of the mailing lists might be preferable.