Ever need to know how to embed an Excel spreadsheet on a website? Just follow Microsoft's clear, easy to follow instructions. There are options for tables, filtering content and dynamic user created calculations. I could see this being a great way for students to add lots of data to a web based report. I also like the interactive nature where user input can modify a chart. It could be helpful for testing trends or making projections.
A little HTML is helpful for creating customized web outputs but since it uses iframes, it's pretty easy. Here's a quick temperature conversion calculator I made.