Mt. Mary needed an event registration form that could both send them information via email and post over to a credit card vendor at the same time. It also needed to be easy to update but had no database or admin system to work through. So I used a php array to allow the client easy access to update the events without the need for them to learn html or javascript. This form includes the ability to add/delete guests and a running subtotal, as well as in-place validations via jquery which are then revalidated via php in case the user has javascript off. Since this was originally posted, however, Mt. Mary has moved on to using a third party for their event registration.