Today it's Donovan's "Season of the Witch". Although it was never released as a single, it was on the Donovan LP "Sunshine Superman", out in 1968. But it's had tons of airplay, been recorded and covered by dozens of bands and artists from Robert Plant to Lou Rawls, it's been in many, many movies, it's been three movie titles, two book titles and appeared on uncounted TV shows... even the Simpsons. Recently the song appeared in the movies "The Other Guys" with Will Ferrell and "Dark Shadows" with Johnny Depp. It's also on the list of Billboard's top ten Halloween Songs.