Here is a quickie - the batcave from the dark knight 2008 movie.
Step 1: Outside
Outside it's just a normal storage container.
Step 2: Interior
And on the inside is the batcave from the dark knight! After Wayne manor was destroyed, Bruce Wayne created this as a temporary batcave. Seen in both dark knight and the dark knight rises.
Complete with luminous ceiling, main computer, furnaces etc. this was created within a period of 2 days, with 20 minutes each fat :)