UFC 66: Liddell vs. Ortiz 2 was a mixed martial arts event held by the Ultimate Fighting Championship on December 30, 2006 at the MGM Grand Garden Arena in Las Vegas, Nevada [3].

UFC 66's main event was a championship fight with two of the UFC's biggest light heavyweight stars, Light Heavyweight Champion Chuck Liddell defending his title against former champion Tito Ortiz. This fight was first announced by Ortiz at the UFC 63 weigh-ins on September 22, 2006.

The co-main event saw Forrest Griffin take on "The Dean of Mean" Keith Jardine. The card and also saw the return of Andrei Arlovski and The Ultimate Fighter 3 winner Michael Bisping's first bout in the UFC since winning that season. During the event, it was made official that Mirko "Cro Cop" Filipovic had signed a contract with the UFC, and would make his debut with the organization at UFC 67.

The event was the UFC's first show at MGM Grand Arena since UFC 56, and was nearly sold-out, producing the highest live gate revenue in North American mixed martial arts history, extending the previous record at UFC 57 by over $2,000,000 (USD). At the time, it was estimated to be the UFC's biggest pay-per-view success with just over 1 million buys.

Charles David "Chuck" Liddell (born December 17, 1969) is a retired American mixed martial artist and former Ultimate Fighting Championship light heavyweight champion. Liddell has an extensive striking background in Kempo, Koei-Kan karate and kickboxing, as well as a grappling background in collegiate wrestling. Liddell is known for his Knockout power, Iron chin, Excellent counter striking and for his sprawl-and-brawl technique, which made him one of the most difficult fighters to takedown. He is one of the most dominant champions that ever competed in the UFC. He still holds the record for the most knockouts in UFC history. As of his retirement, Liddell has had 23 fights in the UFC. Along with fellow UFC Hall of Fame fighter Randy Couture, Liddell is widely credited for bringing mixed martial arts into the mainstream of American sports and entertainment. On July 10, 2009, he was inducted into the UFC Hall of Fame.

Liddell began studying Koei-Kan karate at the age of 12; the tattoo seen on his scalp reads "Koei-Kan". Liddell was a four-year starter on the football team at San Marcos High School. While growing up in Santa Barbara, he often frequented the infamous Del Playa Drive, the middle of the party scene of the college town of Isla Vista, where he often found himself in fights with drunk college students. He became a Division I wrestler at California Polytechnic State University, San Luis Obispo and graduated with a Bachelor of Arts Degree in Business/Accounting in 1995. He holds an amateur kickboxing record of 20 wins and 2 losses, with 16 of his wins coming by way of knockout.

Michael Gavin Joseph Bisping (born 28 February 1979) is an English mixed martial artist. He fights in the middleweight division of the Ultimate Fighting Championship and is the former Cage Warriors Fighting Championship Light Heavyweight Champion, former Cage Rage Light Heavyweight Champion and The Ultimate Fighter 3 Light Heavyweight Tournament winner. As of March 2012, Bisping is ranked the No. 4 middleweight in the world by Sherdog.

Bisping was born in manchester UK in 1979, but moved to Bridlington, East Yorkshire, England when he was a child. Taking an early interest in martial arts, Bisping began training in a traditional form of jiu-jitsu known as Yawara Ryu under Paul Lloyd Davies when he was 8 years old. In 1994, at the age of 15, Bisping competed as an amateur in England's first "no holds barred" competition, a precursor to modern MMA, called Knock Down Sport Budo (KSBO), organised by Davies.

At the age of 18, Bisping decided to abandon his martial arts training in order "to pursue real life". But less than a year later Bisping began training kickboxing and karate on the advice of Alan Clarking, owner of Black Knights gym, who saw potential in the young fighter. Bisping enjoyed a short, but successful kickboxing career, winning the North West Area title and later the Pro British light heavyweight kickboxing title. After again briefly quitting competition in 1998, Bisping returned to kickboxing to take the Pro British light heavyweight title for a second time. Soon after winning his second kickboxing title, Bisping was forced to abandon his full-time training for a "real job". Bisping worked in factories, slaughterhouses, as an upholsterer, a postman, a tiler, a plasterer, a double-glazing door salesman,production line operative making barbecues at Rectella in Clitheroe and also a relatively successful DJ around the north-west club scene.

Jacob Christopher "Tito" Ortiz (English: /tɪtɵ ɔərtɪs/) (born January 23, 1975) is an American mixed martial artist and former UFC Light Heavyweight Champion, having held the title from April 14, 2000 to September 26, 2003. Along with fighters like Randy Couture and Chuck Liddell, he was one of the sport's early stars. Ortiz ultimately became the biggest pay-per-view draw of 2006 for his fights with Liddell, Forrest Griffin, and Ken Shamrock.

Outside of his fighting career, Ortiz is the CEO of the Punishment Athletics MMA equipment and clothing line. He also owns an MMA training gym called Punishment Training Center, which is located in Huntington Beach, CA.

Jacob Christopher Ortiz was born to Samuel and Joyce Ortiz. He received his nickname "Tito," which means tyrant, from his father when he was a year old. He is the fourth child of his mother, Joyce, who had three sons from a previous marriage. His mixed heritage (Mexican father, American mother) has been reflected in his ring entrances as he has borne both Mexican and American flags.

Janigleison Herculano Alves, better known as Gleison Tibau (Portuguese pronunciation: [ɡlejˈsõ tʃiˈbaw]; born July 10, 1983 in Mossoró, Brazil) is a Brazilian mixed martial artist. He currently fights for the Ultimate Fighting Championship. He is one of the largest lightweights in MMA, weighing up to 183 pounds by the time he enters the cage.

He was brought up as a fighter in Kimura team, from the northern part of Brazil. Today Tibau trains at American Top Team. Gleison's biggest strengths are his conditioning, wrestling, size and his Brazilian Jiu-Jitsu.

Originally a welterweight, Tibau made his UFC debut against a strong Nick Diaz. Tibau started strong and was taking Diaz down efficiently using his Jiu-Jitsu. In the second round he tired and lost by TKO due to strikes.

After the fight, Tibau took on Jason Dent at UFC 68. Tibau dominated the fight and won by decision. He then took a one fight hiatus from the company and returned defeating Jeff Cox. Tibau then took on undefeated Terry Etim, Tibau won the fight by decision.