http://qntm.org/responsibility is an interesting go at it, and where I first learned of the concept. His other fiction is pretty fun, as well.

Very nice story indeed :D In the story, the characters talk about nested levels of simulation and how slightly disheartening is to know that they are not in the top layer, therefore not "real".

Afai(!)k, there might as well not be a top layer but infinite nesting -- or, even more charmingly, endless recursion, each simulation containing not another layer, but another iteration of itself. This at least would eliminate the embarrassment of being "less real" than the above layer.

That's really quite cool. Thanks for that :)

--edit-- My own thoughts were along the lines of - humans decide we're probably in a simulation, and try to figure out how we could attempt communication with the simulators. To do so we decide to build our own simulation, then run it at double speed and watch how they try to communicate with us. Then recurse...

If you ever read a story like that, you'll know someone with the same idea but more motivation than me wrote it :)

Already exists, well at least the movie does - http://www.imdb.com/title/tt0139809/

edited: initially linked to the wrong movie