OMG! I love this!
Sculptris 1.0 is something you need to witness than read it here. Here is a simple trailer and a simple introduction to it.
Sculptris 1.0 is a super cool software developed by a Tomas Pettersson in a span of 6 months. It is incredibly cool and may save your worthy time. This is free. And of course you ll not mind donating some money for it. It is a 3d modeling software. I don't want to compare it with Blender or something of that type, but this is definitely great! You get to do simple stuff the simple way rather than what it is with Blender which is simple or difficult stuff it is always the difficult way.
And it is incredibly portable. Download it from sculptris.com the 3mb zip package. Yup, its all about it. No installation nothing. Extract files to a comfortable folder and just run the application. You're done and ready to make incredibly cool 3D designs. Just check out his forum for more brushes and cool stuff. :)