I discovered that there might be a bug in Blender 2.66 (RC). If you edit an object in sculpt mode with dynamic sculpting, the inflate brush could mess up the model and freeze the computer, adding very large amount of geometry.
Here is a video I made, which shows what I mean. I did not found a bug report covering this. Sadly, my english is not good enough to make a bug report.
(Using Blender 2.66 RC on a ubuntu linux machine. Dell Vostro 220.)