Developing a theatre site with ticket purchasing

So this past month I have started a creative marketing firm and as a way to market myself I have thought about developing a website for the town's award winning high school theatre department totally free of charge. I've been trying to come up with a high profile site that would serve the community; but also make very visible my firm. (I hope this makes sense) Has anyone else done anything like this, does it work?

Second a feature i've been wanting to use, is giving people the ability to buy tickets online. But the 999 seat theatre has assigned seating, I have no idea how I would do this in terms of having people buy specific seats. I know places like ticketmaster does it, but I have no clue how, any thoughts?

Would be a simple script with PHP, Ruby on Rails, or any other server side scripting of your choice.

This wouldn't be a script for a beginer to take on. I would advise searching Google and script sites for a premade script that you can fit to your liking.