yet another reason that I love ruby / rake, vs nant

nant-build-file.xml

	<target name="compress.css" verbose="true" description="compress the css files">
		<foreach item="File" property="file.path">
			<in>
				<items>
					<include name="css\*.css" />
				</items>
			</in>
			<do>
				<property name="filename" value="css\${path::get-file-name(file.path)}" />
				<exec program="java" commandline="-jar ${tools}\YUICompressor\build\yuicompressor-2.4.2.jar --type css -o ${filename} ${filename}" />
			</do>
		</foreach>
	</target>

ruby-rake-code.rb

Dir.glob("css/*.css") do |f|
  filename = File.basename(f)
  system "java -jar ${tools}\YUICompressor\build\yuicompressor-2.4.2.jar --type css -o ${filename} ${filename}"
end