I’ve gotten this one too. I believe there was a nugget of truth in it at one time: Mars, as viewed through a decently sized telescope, would have been as large as the full moon is to the naked eye. Or something to that effect. There are several big images in the middle of the email which break up the sentences in an awkward way. After many forwards, cutting and pasting, it gets further and further from the truth. (Not to say this was completely true to begin with- like most things, I think it started with a bit of truth, some good intentions, and a lot of stupid.)
Mars is quite interesting though a telescope, regardless of its size. . . You can note the growing and shrinking of the polar ice caps, see global dust storms (in the dulling of the planet), and see albedo differences over the mid-lattitude areas. It takes some getting used to; the more you look at the planet through a telescope the more details you can discern.