That is really great! I think the dress code depends on location, location, location! Also the price of the tickets also gives a little clue too. But, anyways, I believe that for something really formal you will want to if your a man invest in renting a tux or a really nice suit. If your a woman a long dress should do. You can pick the color if you want but classy colors like red, black, etc. are the best. If it is not as formal for boys just wear a nice button up shirt with some nice pants. If your a girl you could pick the same color dress and\or style but a little shorter. Well i hope you have fun at your concert!!