The Ying Yang Twins will perform during this year’s ski trip to Copper Mountain, Colo., the Northwestern Ski and Snowboard Club announced Wednesday. Extra money from promotions last year allowed the club to finance the performance, with no extra cost for students – the concert will be free for everyone going on the trip. Tickets for the trip went on sale for students Oct. 12 and are now open to non-NU students as well through Friday. They can be bought online through the Norris Box Office.