Electric motor-driven rotating platform for adults

[harry]

I am trying to construct a wood platform that rotates both clockwise and counter - clockwise. It needs to be able to hold an adult and be propelled by an electric motor that can be operated from a short distance from the platform. It doesn't need to be fancy, I just need it to rotate people at a decent speed. I have some basic ideas about the construction, but don't know what mechanical parts to use. Please help me figure this out.

 

[Ivan Seeking]

What are your ideas, how much can you spend, and what are your resources for parts?