It's pouring rain early on Saturday evening, and most vassals operating at the Green Castle food-cart pod have decided to flee the fields early. But Ian Griffonwyd of Nargila Garden hookah cart (1930 NE Everett St., stands his ground. Under a towering green canopy that gives the quiet side-street pod its name, Griffonwyd carefully sets four small blocks of charcoal on top of an ornate Syrian water pipe and lights up a blend of tobacco and fruit for his only customers. As the clouds empty, Griffonwyd, sternly dressed for a cart operator in a black dress shirt and maroon necktie, sets down his own rig and proceeds to tell the legend of Portland's first hookah cart, which he opened on Northeast Alberta Street last year and recently reopened here after taking the winter off. He says his customers like to linger and will often puff lackadaisically on the same $14 bowl for an hour or more. Unlike most busy food-cart owners, Griffonwyd likes to chat. And so you do, enjoying nicotine-fueled conversation as rain falls in the otherwise unoccupied parking lot.