This is one that many people are familiar with but I think it is a good one to post here because the children enjoy it so much. Prezi.com is a site that you can create sleek presentations on and is very user friendly. It is like an updated PowerPoint, but with no slides. Everything is created on a blank canvas. This week I had students create a Prezi about the prefix "re". They would write sentences and one of the words must use the prefix "re". Example: I had to redo my homework.
From there students selected pictures (built into prezi) that matched their sentences and created an entire presentation on this concept. The students really enjoy this site. I found that over the weekend I had students continue working on their presentation (not a requirement). Give this website a look if you haven't done so in the past.