This has been popping up a lot more recently and by more serious scientists.
One of the most compelling arguments I've seen for living in a simulation is that we're discovering that reality in this universe is pixelated so to speak. Things have a finite minimum size. Planck length, sub-atomic particles, minimum quanta of energy etc. Why would there be finite minimums?
Then the second argument has been that things like the quantum observer effect (observing an event changes it's outcome) seems a bit like the optimisations and cheats game programmers would use. For example if you're not looking in a certain direction, why spend processing power rendering it?
Like one of the previous posters also said - if this technology will eventually become possible to us, then we have to assume that we're already in a simulation, since it's extremely unlikely we're the first incarnation of our species, rather than the multitude of nested simulations which followed.
All very interesting. And really - does it even matter - we are what we are and if reality is "good enough" then so what?! ;-)