YUI Compressor for NAnt
I had my first go with NAnt just a few hours ago and it was so easy, I am already porting my batch scripts over and creating build scripts with a few good examples off the web as my starting point.
I came across the JSMin task for NAnt which was pretty good but not as good as YUI Compressor. I came across a .NET C# port of the JAVA based YUI Compressor and also found a custom task for it but no DLL. I threw the two together with the latest .NET port of YUI Compressor and put it up on my projects for download under NAnt task for YUI Compressor.