I came across the Climate Wizard a few weeks ago and have been playing around with it since then.  It isn't too complicated and gives students (and teachers!) an opportunity to explore a number of different aspects of climate change science including historical temperature and precipitation averages, and future climate predictions based on a number of different model scenarios.   The Wizard is a good way to introduce models, how they work, and why different models show different prediction results.  It also is a good example of ways to illustrate numerical data visually.  One thing I thought was interesting was the button in the upper right hand corner that allowed you to get the values that were used in creating the model.  This seemed like a great teachable moment.

Tools like this that allow students to customize their experiences working with data and essentially give them a chance to "play" a bit, are great starting points for discussions aroud climate change science, how to represent data and the complicated world of modeling and predictions.