Ben Wilson's Chewing Gum paintings and Slinkachu's sculpture rewards the attentive pedestrian. The former paints tiny pictures on sidewalk gum. The latter sets up tiny urban tableaus with humor and sly social critique. Pays to watch where you walk. (hat tip -- Raw Vision)
The work of Russian miniaturist Nikolai Syadristy is amazing - sculptures, watercolors, engravings, all mere millimeters in size. It's a shame, however, that the best online galleries for displaying his works are so limited. This Flash based virtual museum and this horrendous gallery were the most extensive collections available online. Still, his work is worth suffering through the bad user interface & limited English translation to enjoy, for those who wish to know just how many angeles truly can fit on the head of a pin.