class HelloWorld
   include MsBuild::Task

   parameter :message

   def execute
      log.log_message :message
   end
end

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <UsingTask Name="HelloWorld" TaskFactory="IronRubyTaskFactory" AssemblyFile="MsBuild.IronRuby.dll">
        <Task>
            <Script Path="hello_world.rb" />
        </Task>
    </UsingTask>
</Project>

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <Import Project="my.ruby.tasks" />
    <Target Name="Build">
        <HelloWorld Message="Hello IronRuby task" />
    </Target>
</Project>