I just tried Sculptris for the first time. (A free and light version of Zbrush, a digital modelling software). As a CG artist who mostly loves lighting and rendering (because the payoff is a beautiful image, as opposed to modelling, where you're rewarded with a still bland looking grey shaded preview), One of the things I lamented most about 3D modeling, which I generally hate, is the unintuitive idea of pushing and pulling vertices and polygons around, keeping geometry clean, and worrying about topography, and intersecting geometry. Ugh... Like most creatives, I'd rather just get to the business of creating cool looking things without much worrying about breaking something. (Although breaking things can sometimes result in happy accidents).
Enter Sculptris. Using a paintbrush to push and pull organic blobs around, this bad boy automatically subdivides the geometry only where you add detail and tries to rebuild the mesh cleanly every time you add a brush stroke. Dynamic tessellation is what they call this genius automation, which is great because I couldn't care less about retopologizing models once I've already done the fun creative part. (Retopologizing is essentially rebuilding the model cleanly for animation in low res, after you've built the high res one).
Very fun tool, more experiments to come.