Go to the concert, but I've been trying to give this advice to people for years, but many in my circle don't listen. When you get your new calendar each year, immediately cross out certain dates on January 2nd. For me I immediately cross out ACCT, first 2 days of NCAA's, and write in all known football game dates and hoops dates. I'll even cross out days like "Masters Sunday" or "Yankees opening day" It doesn't mean I can't schedule anything to replace those days, but I'll have to see those events before I decide to trump them.