CodeProject has some gems in it.

I friend linked me to this the other day and it changed how I program.  It's not very often that one article changes the way I handle coding but this allowed me to clean up a lot of code.  From the work in the article I have added one more function as well.

public static TResult Let(this TInput o, Func evaluator, TResult failValue)
            where TResult : class
            where TInput : class
        {
            if (o == null) return failValue;
 
            return evaluator(o);
 
        }

This one allows for the calling of functions that return a value.