I have always loved the concept of Socrative.com. Web-based tools that work across platforms are great for technology coaches like myself because no matter what school I visit, it will work. It is a great way to assess students as you can quickly gather data and either have a feel for what they need to know or have already learned. Socrative has recently have changed things up a bit and the environment of Socrative may look new to you the next time you stop in to create a few activities.
Here is a quick preview:
What I'm excited about is the Youtube channel they have created with video tutorials. This will save me a lot of time as I'm accustomed to making my own. I also plan on using this channel for an upcoming online training course I'm building for my staff. It is still developing, but I plan to launch it soon.