Distortraits, celebrity caricatures and other digital illustrations

Hi,
Here's a portrait I did to practice, although what I really like are caricatures, here I didn't exaggerated anything, I sketched away in photoshop without stopping for 1 hour, just to see what I could do in that time, and I never checked once the resemblance, instead I concentrated merely in the lines and spaces in between them and the values, it is easier if you convert the photo in grayscale to sketch with values.