title: How can I create an Excel compatible Spreadsheets on the server side in C#?
body: <p>I'd like to make server-side excel compatible spreadsheets that maybe use OpenXML or a structured data format.</p>
  
  <p>I've used Office Interop before to generate Excel spreadsheets, but those apps run on a PC that has office installed.</p>
  
  <p>For this web project I'm building, the server doesn't have Office installed (and they don't want to buy it).</p>
  
  <p>What's the best library for me to use that allows me to generate Office compatible spreadsheets from a windows server 2k8 using IIS7?</p>
  
  <p>Some additional requirements:</p>
  
  <ul>
  <li>Ideally, free</li>
  <li>Allows for simple cell formulas that can be inserted at runtime</li>
  </ul>