Paul Rudnick is sort of a curse upon movie comedy. I don't mean that as a cheap shot--what I mean is that he is a very, very funny writer, but that he only remains that way when you *read* his stuff; seeing it actually acted out onscreen usually kills it. His screenplays must read as funny as anything else he writes, but they almost never make it as actual movies.
So, with this in mind, I tried watching 'Marci X' at arm's length, imagining it as a Paul Rudnick satirical short story instead of a movie comedy. It sort of worked. I don't think this is the incredible disaster it's reputed to be (not that it's very successful); it's more on the level of painless, pleasant-ish time-killer. Lisa Kudrow is solid as usual. Being familiar with Rudnick's writing style helps. Oh, and you have to pretty much ignore any possiblity that this might have anything to do with society as we know it...did I forget to mention that?