1. "You're Gonna Miss This" country singer's 50th birthday if you don't wish him Happy Birthday on January 13.
2. This Guns 'N' Roses singer will have an appetite for birthday cake on February 6.
3. Will he invite his "Friends in Low Places" to his birthday party on February 7?
4. "If It Makes You Happy," wish this singer/guitarist a Happy Birthday on February 11.
5. 50 candles will provide a "Blaze Of Glory" for this singer/band namesake on March 2.
6. You could walk 500 miles, and you could walk 500 more, to wish this duo (twin brothers) a Happy 50th on March 5.
7. This rapper won't be "Too Legit to Quit" partying on his 50th birthday on March 30.
8. Born Jeffrey Isbell in Lafayette, Indiana on April 8, 1962, what name did he use as a guitarist for Guns 'N' Roses?
9. He might invite his former band members in The Cult or in The Doors of the 21st Century to his 50th birthday on May 14.
10. He'll wear his "Sunglasses At Night" on the evening of his 50th birthday on May 31.
11. Fellow American Idol judges Simon Cowell and Randy Jackson will probably "Rush Rush" to her 50th birthday party on June 19.
12. What if God was "One Of Us" celebrating her 50th birthday on July 8?
13. Motley Crue's drummer (and a sex tape star) will have lots of "Girls, Girls, Girls" at his 50th birthday on October 3.
14. Three of the Red Hot Chili Peppers are turning 50 this year; the first, the bass player, will celebrate on October 16. What name does he use professionally?
15. And then their drummer has his 50th on October 25 - who is he?
16. And then, their lead singer turns 50 on November 1 - who is he?
17. You'd be "Unforgiven" if you forgot the 50th birthday of this lead guitarist of Metallica on November 18.

Bonus: He now calls himself Sananda Francesco Maitreya, but what was this "Wishing Well" singer, turning 50 on March 15, known as during his hitmaking days?