I've been using my "between contracts" time to do some in depth sharepoint webpart development using the Visual Studio 2008 extensions. On the second deploy of a custom webpart I receieved a rather unhelpful error:
"Value does not fall within the expected range"
Not much on google about this on but I eventually tracked down a blog post from Brian Madsen with a workaround. You can read Brians post for all the gory details but to cut a long story short try the following in your prebuild event:
rd /S/Q "$(ProjectDir)pkg\"
Works on my machine !