see SQL script above and then:
LinqMetaData metaData = new LinqMetaData();
metaData.CustomFunctionMappings = new FunctionMappingStore();
metaData.CustomFunctionMappings.Add(new FunctionMapping(typeof(GuidExtensions),"Random",1,"dbo.fn_newID({0})"));
var result = ( from t in metaData.Tips
orderby GuidExtensions.Random(t.TipId)
select t).FirstOrDefault();
and for guidextensions.cs
public static class GuidExtensions
{
public static Guid Random(Guid id)
{
throw new NotImplementedException();
}
}