Siegel's 1941 at El Cortez is old-school cool, with a twist of sophisticated style. All Day Menu Overnight Menu Dessert Menu Cocktail Menu. A Prime Opportunity. Morning, Noon, Night. When you're done tearing up the gaming floor, tear into a beautiful Prime Rib at Siegel's 1941 for only $16.95. The Cortex Prime book is intended towards those who will be running games, and for that reason it’s laid out a bit like a menu. Although the first 45 pages are about the ‘core rules’, after the initial 8 page primer those core rules are already full of rules mods, reducing the linearity of the chapter.