Mardi Gras celebrations get a head start this weekend at Jimmy's No. 43, 43 East Seventh Street (Second Avenue), in the East Village. On Saturday from 1 to 3 p.m., a hot-sauce tasting of at least a half-dozen varieties will be featured. The $10 admission at the door will help benefit the Rootstown Organic Farm in Rootstown, Ohio, which was ravaged by a hailstorm last spring. And on Sunday from 1 to 3 p.m., the restaurant holds a gumbo cook-off to benefit Chefs for the Marcellus, a group that works to protect upstate water and farmland from hydrofracking for natural gas. The $20 admission at the door is for unlimited tastings. At Gravy, 32 East 21st Street (between Broadway and Park Avenue), in the Flatiron District, the chef Reagan Angelle, a Louisiana native, serves up a $45-per-person Mardi Gras prix-fixe menu Friday through Tuesday. Proceeds from "The Bacchanal" drink special will be donated to the Make It Right, which is helping to rebuild the Ninth Ward in New Orleans. Rio de Janeiro's festive Carnival celebrations are also taking place in New York. On Saturday from 9 p.m. to 1 a.m., Sushi Samba, at 245 Park Avenue (East 20th Street) and 87 Seventh Avenue South (Barrow Street), will have a party with food and drink specials, samba dancers, music and live video feeds of the Brazilian fete. Zum Schneider, 107 Avenue C (East Seventh Street), in the East Village, will have Carnival parties every night until Feb. 21 with cabaret shows, costume parties and special German beers on sale. Tickets are $18 in advance, online or at the bar, or $22 at the door. The guest sommelier program at A Voce Madison and A Voce Columbus, at 41 Madison Avenue (East 26th Street) and 10 Columbus Circle, respectively, wraps up this weekend with dinners on Friday and Saturday. The $95 four-course prix-fixe menus will give guests the chance to talk intimately with the sommeliers, who happen to be the winemakers, promoting their labels and the restaurant's wine list. The chef Amorette Casaus of Ardesia, 510 West 52nd Street (between 10th and 11th Avenues), in Hell's Kitchen, leads a hands-on class on pasta-making basics on Saturday from 2 to 4 p.m. Students will learn how to roll out various shapes of pasta while enjoying snacks, wine and draft beers. The class is $40 per person (which doesn't include tax and tip but does include the food and drinks). To reserve a spot, e-mail info@ardesia-ny.com or call (212) 247-9191. Farmers from the Finger Lakes region who grow grains and sell them under the label Cayuga Pure Organics will give a talk about their products while conducting a tasting with beer pairings on Sunday at 4 p.m. at Brooklyn Kitchen, 100 Frost Street (Leonard Street), in Williamsburg, Brooklyn. While the session is free, online registration is required. In honor of Presidents" Day on Monday, Hill Country Barbecue Market, 30 West 26th Street (between Broadway and Sixth Avenue), in Chelsea, is serving a $17 "presidential manhattan" made with Jefferson's Rye, a line of handcrafted whiskey named after the third president. The drink special is available through the end of February. Danny Meyer's Whitney Museum restaurant Untitled, 945 Madison Avenue (East 75th Street), on the Upper East Side, has dropped its prix-fixe menu and rolled out an à la carte menu. Dinners Thursday through Saturday now include items like a trout B.L.T. and stuffed chickpea crepes. Reservations can be made online. Monkey Bar, 60 East 54th Street (between Madison and Park Avenues), in Midtown East, has extended its bar hours until 2 a.m. Monday through Saturday. The bar menu and cocktails, including newer ones from its mixologist, Julie Reiner, and head bartender, Bryan Schneider, will be served.