Rod Paddack gave this session wearing a great geek shirt. His enthusiasm for open source was reciprocated by many in the audience. Here is the list:

• SharpZibLib Compression Library
• PDFSharp.com creates PDF files
• CruiseControl continuous build system - never upset a build master
• Nant another build tool
• NUnit a developer's unit test framework
• NHibernate - persisting plain .NET objects to and from an underlying relational database
• DotNetNuke - mega portal system in VB.net
• AJAX Asp.Net ToolKit - very cool AJAX controls
• Ghengis - don't know what it really does but the website has other interesting tools
• MySQL - not sure how open source this really is
• ConnectionStrings.com - this one I need
• CodePlex.com - open source code repository
• Thoughtworks.com - lots of stuff
• Microsoft Patterns and Practices - cool stuff
• Code.MSDN.COM - for small bits of code snippets instead of the big stuff at codeplex

Mentions during session included http://code.google.com/

What are your top tools?