Here is a minecraft world cake I put together. Really quite easy and very popular! We went out for laser tag for my son't birthday and several people came up to take pictures of the cake!
I made a double batch of chocolate cake (I only make cakes from scratch, I use the Betty Crocker Best Chocolate Cake recipe)
I baked this in a 1/4 sheet cake pan.
I then cut out hunks of cake and assembled them on a Simple Additions large platter from Pampered Chef. The plate measures 15 inches square to give you an idea how big the cake was.
Underneath and in between layers, I put a thin layer of chocolate filling to keep the layers from shifting. Then I put a flat layer of green frosting on the top of each section. The recipe I use is 1/2 cup shortening, 1/2 cup butter, 1 Tbsp vanilla, 1/2 Tbsp meringue powder, 4 cups powdered sugar and approximately 2 Tbsp milk to thin.
I thinly sliced rice krispie treats to create the beach. I used a sharpie to draw the squid directly on the plate, then covered the water area with blue gel icing.
The trees are make of cut up rice krispie treats. I then mixed food coloring, 1 Tbsp corn syrup and 1 Tbsp water to make a paint for the trees. I'd let this dry at least a day before using, as it was a little gooey. Otherwise, dry them with a hairdryer. The tree trunks are kit kat bars. I inserted toothpicks at each end to attach the tree top and to stabilize in the cake.
Steve, the Creeper and the pig came from http://www.fps-x-games.com/2012/04/minecraft-mob-printable-cut-out.html
However, the creeper is bigger than Steve, so you may want to google minecraft papercraft to find a different set.