The Grateful Dead rose out of the counterculture of Haight-Ashbury in 1965. The band never went mainstream, but it developed a huge and devoted following of that turned up by the tens of thousands with their tie dye and bongs whenever the band came to town. Jerry Garcia, the band’s talisman and leader, died in 1995. But for the last 50 years, the Dead’s music has just kept on truckin’, handed down from one generation of pot-smoking college kids to the next. The latest evidence is “Day of the Dead,” a giant tribute box set of 59 tracks and more than five hours of music. A who’s who of indie artists contribute songs to the set, including The National, Jim James, Mumford & Sons, Bonnie Prince Billy, Courtney Barnett, and The War on Drugs.