Lego all the way. Unluckily I got few, so I used mostly those of my friends. I use Lego to compensate my lack of toys. I mainly build transformers, but also even games. I build a labyrinth you moved through with your finger blindfolded. I tried to build a labyrinth for guinea pigs, although it came out smaller than I wanted. I build two torsos with sticks from their forearms, the goal was to hit the chest of the other, which would have made the head pop. What I revere as my greatest creation came out of a duel with my cousin. I made a Lego piggy bank in which the lowering of the mandible allowed to open a leg, revealing the hole from which you could take money out. The duel was for my cousin to try to find the mechanism in my piggy bank without dismantle it. The piggy bank didn't last much, but then I build a box with a mechanism similar to a lock. Technically, it had only 256 combinations in the key, but he gave up on that.
I just have too few Lego, otherwise I would like to build Macross' Valkyries.