Cocoa#

This is really a cool project, kind of extending Mono on Mac OS X.

From their developers:

We are a fairly new project, and this website is even newer. The project itself revolves around three core tasks. (1) Build an easily installable binary installation of the Mono core runtime. (2) Build an easily installable and fully usable implementation of the Cocoa development API that can be used from the Mono C# environment. (3) Document and make those tools readily available.

Our current status is that the first core task, that of building a runtime, is largely complete. We have the current Mono Project runtime built and a binary installer prepared, and avaialable directly from the Mono Project website. The second phase, known affectionately as 'Cocoa#' is approaching it's second pre-release revision. 0.2 is a big step forward in functionality and usability. With it in place, we will be in a position to begin active development of Cocoa# based applications running on Mac OS X.