I am going to assume that you have an idea on how to cut and assemble wood into a frame and that you know how to attach plywood to that frame. If not, I am sure there are Instructables that will help you.
The main problem I have with building something that is not going to be used all the time is STORAGE! Unfortunately, there is a LAW that states "The more things you build, the less space you have". To get around this law, the things I build are designed to dissemble as much as possible. SO, when a stand alone Fortune Teller Booth was wanted there was a problem. The booth was to be three solid sides (the fourth being just spacers) with a bottom pan that the sides could fit into and a top pan that would go on like a top to a shoe box. All no problem. When not in use the booth was to break down (the shelf in front to fold up) into five lay flat pieces. NOW the problem, how to strongly join the sides yet allow for easy dissemble? After thinking hinges, wing nuts and other forms of hardware, I found "Selby Interlocking Flushmounts". Sets of these items are used for hanging mirrors and panels from walls and are very strong. Twelve sets were used to make the booth. In the area where I live they were not available, in fact when I showed a set to some hardware stores they said they had never seen such an item. I ordered mine from thehardwarehut.com.
The pictures show the general build, the box is two foot square and six foot tall. The window is something I found in a yard sale a few years back. It is just brightly painted plywood with some spindles and molding attached.
Finally for all you Doctor Who want -a-be's, I am sure you have already seen that with a different molding treatment and top, the booth could just as easily be a Tardus!