I don't know if the Onion has done something along these lines, but I think this would be funny:
Woman appearing to be on cell phone was actually talking to herself
HOUSTON, TX-Lisa Jones was spotted near the intersection of Maple and Pearl talking outloud to no one in particular on Tuesday afternoon. Due to the popularity of headset attachments on cell phones, many of the passersby believed Ms. Jones was talking on one. Jones, self-diagnosed with bi-polar disorder, said she was conversing with one of the many voices in the "room full of voices" she hears in her head. No word if any charges were filed as Ms. Jones was whisked away in a straightjacket.