Check out Proven Winners website and search for shade plants. Lots of ideas there.

Here is a link that might be useful: Proven Winners

pot up a few hosta.. and move them in and out ....

hosta are shade tolerant... but i think you will be hard pressed to find something that likes the dark, all the time ....

if you had 3 hosta .... each week you could move a new one into the dark .... and then it will have 2 weeks in brightness before it has to go back

good luck

ken