I Did Not Know That!?
In 2002, Ukrainian Grandmaster Rusian Ponomariov defeated countryman GM Vassily Ivanchuk in the finals of the 2002 FIDE World Chess Championship by a score of 4½/2½ to become FIDE World Champion at the age of 18; the first teenager and youngest person to ever become FIDE World Champion! On Ponomariov's 20th birthday, October 11, 2003, he became the first high-profile player to forfeit a game because of his cell phone ringing during play?! This happened in round one of the European Team Championship in Plovdiv, Bulgaria, when Ponomariov was playing Black against Swedish GM Evgenij Agrest. Now, 29 years old, Ponomariov is currently listed as #21 on the official FIDE Rating List at 2733.

In 1999,
an even lesser known 33 year old Russian Grandmaster named Alexander Khalifman defeated Grandmaster Vladimir Akopian 3.5-2.5 to become FIDE World Champion! Now, 47 years old, he is 142nd on the FIDE rating list with a current rating is 2616?!

Furthermore, in 2004, another little know Grandmaster, then 25 year old
Rustam Kasimdzhanov won the FIDE World Chess Ch. after he defeated GM Michael Adams. This "ex-WC" barely makes the 2700 list with a current rating of 2709.

And, finally, who is the youngest person to ever achieve the title of Grandmaster? That would be GM Sergey Karjakin who holds the record for both the youngest International Master, at eleven years and eleven months, and Grandmaster, at the age of twelve years and seven months! Now, 22 years old, Karjakin is currently listed as #6 on the official FIDE Rating List at 2780!

I did not know that, either! LF