NuPack arrived with an interesting debugging tale by Tatham Oddie. It was a great post the way he narrowed down the exception using WinDbg and Reflector.
When I downloaded NuPack, the first I wanted to download was castle ActiveRecord, which unfortunately is not in the package list but there are ELMAH, Castle.Core, Catle.Ioc etc. So start using it and start saving your time.
Scott Gu's Announcing NuPack, ASP.NET MVC 3 Beta, and WebMatrix Beta 2 gives some good links for NuPack and Rob Reynold’s “Evolution of Package Management on .NET” Post (Rob is one of the leaders of the Nu project and is on the NuPack team) gives a good account of whats happening with Nu and NuPack.