tiny Hallowe'en decorations
While looking through their site for more Hallowe'en ideas, I stumbled upon the Evil Mad Scientist Laboratory's instructions on how to combine LCD lights with lego minifigures to make really great, and really small, Hallowe'en decorations. If you can handle (tool-wise and patience-wise) carving something that small, the result is fantastic.
And if you like fooling with Lego minifigs, see also their Lego abominations. These are good for everyday, not just Hallowe'en - I especially like the shark riding the bicycle.
These are SO rad.