It’s a good thing Frank Sinatra is already resting in peace. Because if he saw the frequency with which people are ordering pansy cocktails like vodka Red Bulls and Flirtinis, he’d drop dead with outrage. Time to get back to the standards. Huntington Hotel’s Big 4 restaurant hosts cocktail classes on Tuesday nights, where you can learn to pour old-school concoctions like the original martini (with gin, please), a sidecar deluxe, a Manhattan, and an old-fashioned. Big 4 veteran bartenders will share their hard-earned expertise and samples free of charge. After studying up, you can go impress your friends with your newfound knack for mixing stiff drinks or order yourself another round and listen to the piano player knock out mood-enhancing tunes. Either way, it should keep Old Blue Eyes from rolling over in his grave. Tuesday nights at Big 4, in the Huntington Hotel, 1075 California Street, at Taylor Street (415-771-1140).