StackOverFlow in mscordlib.dll and SiteMap Providers
Word to the wise, unless you want to spend hours tracking down idiotic Stack Overflows, check your Sitemap files in ASP.NET. Each sitemap node can contain a 'Provider' attribute. This is designed so that you can set up several sitemaps, and have a master sitemap file pull submenuitems from seperate sitemap files (or databases, depending on your sitemap provider configuration, and whether you rolled your own. However, if you mistakenly point a sitemap provider node to the same provider that references the sitemap file you're in, you'll get a stack overflow error. This was tricky because its actually the webserver that blows the stack, so you can't debug or trace your way out of it. What a fool I've been :)