During a Hackathon with a friend we came up with the idea for WhatupNYU.com. WhatupNYU is basically NYU's social life in one site. Backstory: NYU has a lot of social media applications. You can find NYU Secrets, NYU Compliments, NYU Brew, NYU Hookups, NYULocal, Washington Square News, etc. We wanted to simplify that into one little website that gives you the feed for the day, and so we created WhatupNYU.com.
We used basic tools such as jQuery, PHP, MYSQL, and the Facebook API to create it. What we would do is we would cache the incoming data from Facebook from all these groups (including Tumblr groups, excluding images), and repost them when the user visited the site. This would make it a lot faster as the data doesn't have to be loaded again from Facebook. It was a simple hack that actually recieved over 6,000 unique visits on the first night! On the same night we also released a Mobile Version of the site built on Parse and Ractchet.
Later, to help grow community at NYU we built a new function called: People. People is basically a way for individuals to find eachother through tumblr images, tweets, etc.
I've also open-sourced it if you'd like to build your own WhatupNYU. If you'd like to build your own just edit the section layout.js in js.