I'm really glad that we have managed to get a really nice release of the SharePoint Extensions Lib, SPExLib, out. This brand new release (22.214.171.124) has significantly been improved since the first release a couple of weeks ago.
By referencing the SPExLib.dll and include the namespaces you can easily write code like this (taken directly from one of my current projects):
As you can see the sample uses a number of extension methods; SPList.GetItems() can accept a CAML query directly, System.String has a FormatWith method, the SPListItemCollection has a ForEach method.
Download it and try it out, you will find yourself more productive!
Have a nice weekend.