Rule Editor is a web-based business rules authoring and management component. It's free to use and can be referenced from NuGet. It supports all modern .NET platforms; consult the Code Effects Implementation Examples article for implementation details.
Rule Engine is a business rules evaluation .NET component. Its trial version delays all calls to Evaluate() and Filter() methods for six seconds and can be freely referenced from Nuget for testing purposes. The licensed version has no limitations and can be downloaded using a product key purchased from Code Effects Software. See the Licensing page for details.