The Best Band EVER. Period. End of story.
More specifically, a jam band whose music combined rock, folk, blues, bluegrass, psychadelia, country, jazz, and gospel, along with an indescribable sort of magical purity that is apparent to almost anyone who actually takes the timeto listen to it, but is mostly noticed by hippies, stoners, and liberals, all of which I identify with. As a side note, jackasses, bastards, conservative douchebags, mindless capitalist minions, and many people who voted for Bush are immune to this effect.
Members of the Grateful Dead included Bob Weir, Phil Lesh, Ron "Pigpen" McKernan, and of course, Jerry Garcia, may he rest in peace. Some of their better songs are "Jack Straw," "Fire on the Mountain," "Scarlet Begonias," "Friend of the Devil," "Sugar Magnolia," "Cassidy," "Sugaree," "Samson & Delilah," "Box of Rain," Eyes of the World," "The Wheel," "Ramble on Rose," and "Playing in the Band." Their best albums are Terrapin Station, Europe '72, Blues for Allah, Steal your Face, Shakedown Street, and Aoxomoxoa (if only for the album cover.) One major aspect of the Grateful Dead that is dificult to classify was their customized sound system, the Wall of Sound. This sound system had a seperate speaker for each instrument, and was designed so that the music could be heard over half a mile away with minimal degradation. Due to a combination of the Wall of Sound, the evolving nature of the Dead's songs, and their tendency to jam for long periods of time during concerts, the Dead experience was infinitely better live.
Though nearly anyone can enjoy the Grateful Dead, to truly understand the worlds behind the words, one must either be raised on it or attend a few Folk Festivals.
By the way, the people who said that the Dead are "Proof that if you give enough people LSD they'll totally love bad country music." and "an insidious LSD cult... infidelic pagan hippie scum... a tool of the government... etc." should rot in hell for all eternity and have a vat of acid poured into their eyes drop by drop, the cock-sucking assholes.
Any Hippie: "Want to go listen to Blues for Allah and watch the tide come in?"
Any Other Hippie: "Sure, the Grateful Dead are my heroes. Can I bring weed?"
Any Hippie: "Got some, just grab a bowl, some Doritos, and six cream sodas."
Any Other Hippie: "Cool."