Quoc: Crystal (born May 6, 1994) is a female capuchin monkey and animal actress, acquired and trained by Birds & Animals Unlimited, Hollywood's largest supplier of animals. Her acting career began as a baby monkey in the 1997 film George of the Jungle. More recently, she portrayed the irritating monkey Dexter in the Night at the Museum franchise, and a drug-dealing monkey in The Hangover Part II. In 2012, she played Dr. Rizzo on the sitcom Animal Practice.

Name of monkey from night at the museum?
HW Chung: OK, some thoughts:
The relevant information to answer the above question is: More recently, she portrayed the irritating monkey Dexter in the Night at the Museum franchise, and a drug-dealing monkey in The Hangover Part II. The answer is Dexter.