<p>What are they and what are they good for?</p>

<p>I do not have a CS degree and my background is VB6 -> ASP -> ASP.NET/C#. Can anyone explain it in a clear and concise manner?</p>

Imagine if every single line in your program was a separate function. Each accepts, as a parameter, the next line/function to execute.
Using this model, you can "pause" execution at any line and continue it later. You can also do inventive things like temporarily hop up the execution stack to retrieve a value, or save the current execution state to a database to retrieve later.