List.ly is a website which allows you to create lists about anything and then share them with others to have them vote on the content. This would be a great way to quickly share a "Top 5" list with your followers on Twitter or friends on Facebook. Creating a list with List.ly was very simple and took no time at all. For each item in your list you add a hyperlink (or not if there isn't one) and then give a title and description (optional). Your list can then be shared socially or with a link. At that point, your list viewers can interact with the content and give their opinion. Check out my "Top 5 Cloud Storage Sites" list and vote for your favorite:
This could be a good way for you to curate the web for your students or even better have them pull content for you. Students could also share five websites, images, video, etc. as a demonstration of an understanding of a topic.