It says 4/20 on the calendar, which means it's time for the mellowest Clash of the Titans in history.

In honor of this special day, we've sparked up a battle between two rock classics whose lyrics offer odes to the pastime we're here to celebrate: Black Sabbath's "Sweet Leaf" and Bob Dylan's "Rainy Day Women #12 & 35." It's a drag, but only one of them can win — and as always in this 100 percent reader-voted series, the choice is in your hands.

Dylan struck first with his song, debuting "Rainy Day Women" as the leadoff track to his 1966 Blonde on Blonde LP. In spite of a chorus whose "everybody must get stoned" refrain rankled listeners who accused him of encouraging drug use, the track was released as a single — and did impressively well under the circumstances, peaking at No. 2 in the U.S. and No. 7 in the U.K. even though Dylan's rambling explanation that the lyrics were actually about "cripples and Orientals and the world in which they live" and "sort of Mexican thing, very protest" only helped convince detractors that he was high on something.

"Sweet Leaf," meanwhile, followed five years later, making its debut on Sabbath's 1971 Master of Reality album. No one denied this track was about smoking pot — it actually begins with a tape loop of Tony Iommi coughing while sharing a joint with Ozzy Osbourne — and although Black Sabbath have never really been a singles act, the album itself enjoyed strong sales, peaking at No. 5 in the U.K. and bringing the band its first Top 10 hit in the U.S.

So which of these songs packs the biggest buzz? It's a tough choice, but you don't need to roll up all your ballots at once — you can keep coming back and casting your vote once an hour between now and April 26 at 11:59PM ET. Check out both tracks below.

Listen to Black Sabbath's 'Sweet Leaf'

Listen to Bob Dylan's 'Rainy Day Women #12 & 35'

See Black Sabbath and Other Rockers in the Top 100 Albums of the '70s