With the release of .NET Compact Framework 3.5 I've gotten used to the extension methods feature which I beleive is a great addition to the C# language. Since .NETCF3.5 is not in ROM for Windows Mobile devices, customers are still using .NETCF2.0 and this means internally we have to support 2.0 for products and projects. Having created many extension methods in CF3.5 sharing them in CF2.0 would be ideal. See here on how you can do this.