When you drive by The Dallas Farmers Market, it looks like a gourdfest this time of the year. But there's more than pumpkins in those sheds. My favorite find is Mark, the mushroom man. Mark sells caviar, smoked salmon, and other luxury foods during regular workdays, but every weekend or so, you can find him in the new shed with a tableful of fresh and dried mushrooms--porcini, chanterelles, black trumpets, shiitake, portabellas, morels. And not only that--mark this down for your Christmas list--he sells a shiitake growing kit. It costs $30 a box and you harvest five or six times, more than making your money back.