Small and fast JSON library for .NET 2.0+/SL4+/WP7+/WinRT and powershell. Includes support for dynamic in .NET 4.0+/SL4+/WinRT. Also includes support for DataContract and DataMember.
paulecoyote/simple-json
JSON library for .NET 2.0+/SL4+/WP7/WinRT with optional support for dynamic and DataContract
C#MIT