NRobot is an autonomous robot fighting game. Instead of directly controlling a robot, the human playing the game must write a program that acts as the "brain" of the robot. The robot will then be dumped into the game arena and must attempt to survive on its own. NRobot is written for the ECMA CLR. It's been tested on Mono and on Microsoft's .NET framework. Currently, it is functional and "playable". It comes with three sample robot implementations, so that "out of the box" you can watch a game. One important missing feature is a security architecture: robot code executes with full privileges. Thus, it's recommended that if you are running any robots from untrusted sources, NRobot is run under a user account with no privileges over files you care about. It's also short on documentation, and the GUI implementations have some rough edges.
OpenHacha is an implementation of the proprietary, Windows-only program Hacha. It is based on the libhacha2 library, a C# implementation of the Hacha program feature set developed by the Dalle project. It aims to provide a graphical frontend and a text console client to manage and create Hacha files. It is developed under the MONO:: platform.
Caffeine is a free high-performance interoperability solution between the Java platform and the .NET framework, with special emphasis on the enterprise variants of such platforms. It makes software originally written for .NET available to the Java platform. It promotes library reuse between Java and .NET by transferring APIs across environments, and allows code written for one platform to run on the other platform with minimal performance degradation. It is powered by Mono, and runs on Alpha, Linux, Windows, Mac OS X, HPPA, SPARC, and s390 systems.