Minecraft wiki entry for Building_a_metropolis, associated text: Teeny Town: Make a little, tiny town! Make the whole population one-block-tall mobs and cave spiders, spiders, small and/or tiny slimes, small and/or tiny magma cubes, and silverfish. Make small houses (you may even think of putting the dragon egg as a roof) out of fences, slabs, pressure plates, and carpet, using fence gates as doors. Use ferns and dead bushes for a touch of plant life. You can also use saplings, but be sure to put them in flower pots, or they'll grow into trees, which are far too big for a town of this scale unless you want a giant redwood forest. If you want to add a touch of Dr. Seuss, place down some alliums to represent Truffula trees. Don't put tall mobs in!
Train Station: Make a subway station with non-functional chairs and clocks, minecarts, and tunnels. Preferably made non-expensive blocks (e.g. stone bricks). A functional station with actual trains will take some redstone skill and time. Also see Tutorials/Train station.