With a Dragon as your mascot, I would try taking the Mythical route. Themes that come to mind are: searching for treasure, gems, gems being rewards or goals students can reach and at each step be rewarded, different gems meaning different levels or rewards. You could apply that to various tasks. From games to mazes to incentive programs. Here is a website with loads of dragon links. http://webtech.kennesaw.edu/jcheek3/dragons.htm.
You might also try http://familyfun.go.com/.
Also, for younger children, you might look into ideas from the PBS kids show Dragon Tales. http://pbskids.org/dragontales/index_sw.html.
Hope these help! Have fun stormin' the castle!