3. Artists could win two Grammys in top categories if they also produced or co-produced the recording.

From 1965 to 1978, artists who also produced or co-produced their winning recordings for album or record of the year won two Grammys -- one as artist and one as producer. This brought three extra Grammys to both Stevie Wonder (who won album of the year three times in those years with self-produced albums) and Simon & Garfunkel (who co-produced two record of the year winners and one album of the year winner). Simon also picked up a fourth extra Grammy for a solo album, Still Crazy After All These Years, which he co-produced.

Other lucky artists who benefited from this rule were Herb Alpert (1965), George Harrison (1972), Daryl Dragon (1975), Fleetwood Mac (1977) and a clutch of self-producing artists who were featured on the Saturday Night Fever soundtrack, the 1978 album of the year winner -- Bee Gees, two members of KC and the Sunshine Band (Harry Wayne Casey and Richard Finch), Ralph MacDonald, David Shire and Kool & the Gang.

The Grammys changed the rule in 1979. From that year forward, an artist could be nominated only once in each of those categories, even if he or she contributed to the recording in other capacities.

4. Two solo albums by the same artist could be nominated for album of the year.

This happened just once, in the Grammys' first year, 1958, when two Frank Sinatra albums (Come Fly with Me and Frank Sinatra Sings for Only the Lonely) were nominated. They likely split the vote, allowing Henry Mancini’s Music From Peter Gunn to walk off with the award. This couldn’t happen today.

In 1989, Tom Petty's first solo album, Full Moon Fever, competed with an album by Traveling Wilburys, a supergroup in which he was a member. Petty was nominated for both albums. This could happen today. The Grammys allow artists to have two album of the year nominees if the second is with a co-nominee (the Petty/Wilburys example) or both albums are with different co-nominees.

5. A track from an album that had won a Grammy could compete the following year.

Paul Simon's "Graceland" won record of the year for 1987, even though his album of the same name won album of the year for 1986. Now, once an album wins a Grammy, the tracks from that album are ineligible for record of the year in a subsequent year.

The Grammy rule: “A track or single from an album of the year winner would not be eligible, because it must be a newly released single from an album that never won a Grammy.”

6. Classical albums could be nominated for album of the year.

In the Grammys' first three years (1958-60), four classical albums -- two by Van Cliburn and one each by Sviatoslav Richter and Erich Leinsdorf -- were nominated for album of the year. The Academy decided that this was comparing apples and oranges. Beginning in 1961, album of the year was designed for non-classical albums only and a separate category was created: album of the year – classical.

7. Old songs could win songwriting awards.

"Unforgettable" had been a pop standard for four decades when it won the 1991 award for song of the year. Nat "King" Cole had introduced the song in 1951. It won the 1991 award after Natalie Cole recorded a new version that featured her father.

Other song of the year winners that had met with varying degrees of success years before they took the award include "The First Time Ever I Saw Your Face," "Always on My Mind" and "Wind Beneath My Wings."

In other categories, "Lean on Me" won the 1987 award for best R&B song 15 years after Bill Withers made it a smash; "If You Don't Know Me By Now" won the 1989 award for best R&B song 17 years after Harold Melvin & the Blue Notes made it a smash; "Layla" won the 1992 award for best rock song 20 years after Derek & the Dominoes made it a hit; and "City of New Orleans" won the 1984 award for best country song 22 years after Arlo Guthrie made it a hit.

Now, "A song…must be either a new song or a song first achieving prominence during the eligibility year."

8. Instrumentals could compete for song of the year.

In 1960, "Theme from Exodus" and "Theme From a Summer Place" competed for song of the year. "Exodus" won. Now, "a song must contain melody and lyrics."

9. Long-deceased artists could receive Grammy nominations.

Mahalia Jackson and Jim Morrison each received a Grammy nomination for best spoken word album eight years after their deaths. Billie Holiday received a nod in that category 14 years after her death.

But that’s nothing compared to country legend Hank Williams, who won a 1989 Grammy for best country vocal collaboration and was nominated in two more categories for "There's a Tear in My Beer," a collab with his son, Hank Williams Jr. The elder Williams died on New Year's Day 1953.

The Grammys tightened the rules thereafter. In 1991, when Natalie Cole teamed with her father on "Unforgettable," only she was nominated for record of the year and best traditional pop performance. (The track won both awards.) The rule now is that artists must have recorded their vocals within the past five years, which rules out long-dead artists.

10. Albums and singles could compete in the same category.

Until the early 1990s, albums and singles competed against each other for performance awards. Here's one of the most extreme examples. In 1971, the double-disc, multi-artist rock opera Jesus Christ Superstar competed for best pop vocal performance by a duo, group or chorus with Sonny & Cher's jaunty single "All I Ever Need Is You," which ran a brisk 2:34. (The other nominees in the category were Three Dog Night's "Joy to the World," Bee Gees' "How Can You Mend a Broken Heart" and Carpenters' hit-studded album Carpenters.)

11. Rock and pop artists competed in the same categories.

Before 1979, rock didn't have its own dedicated categories, so rock and pop artists competed. Among the nominated tracks or albums that would probably have been classified as rock if such categories existed back then: Joe Cocker's Mad Dogs and Englishmen (1970), Janis Joplin's "Me and Bobby McGee" (1971), Queen's "Bohemian Rhapsody" (1976), Eagles' Hotel California (1977), Fleetwood Mac's Rumours (1977) and Jackson Browne’s Running on Empty (1978).

12. R&B and rap artists competed in the same categories.

Before 1988, rap didn't have its own dedicated categories, so rap and R&B artists competed. In 1986, Run-D.M.C's Raising Hell (which contained their classic remake of Aerosmith’s "Walk This Way") and a rap novelty hit, the Chicago Bears Shufflin' Crew's "The Super Bowl Shuffle" were nominated for best R&B performance by a duo or group.