Here are just a few helpful Open Source .NET libraries to help in common development tasks.
FileHelpers is an incredible file helper library that aids in managing flat files and data dumps. The fixed width and mixed mode file support make this library an invaluable resource for any developer that has to support txt file formats.
Common Library provides multiple helpers for a wide variety of needs, including Substitution, Cache, processing queues, schedulers and security classes. Many will find the logging a very helpful resource for quickly creating utilities and extending their current projects.
More resources and examples will come shortly.