|Viva Las Vegas|
|Original Airdate||September 23, 2004|
Viva Las Vegas is the first episode in season five of CSI: Crime Scene Investigation.
Grissom works a nightclub shooting with Greg Sanders, who finally found a replacement in the lab and now only has to pass his final proficiency test. Catherine investigates when a stripper is found dead in a hotel room. Warrick investigates when a man is found electrocuted in his bathtub. Sara and Nick are called in when an 'alien' is found in a shallow grave near Area 51.
- It's revealed that Greg has finally found a replacement named Chandra Moore to take over his position in the DNA Lab.
- As a result of not clearing the restroom and peeing in a toilet at the nightclub, Greg fails his final proficiency test but Grissom decides to give him another chance.
- Unable to cope with the rest of the team comparing her to Greg, Chandra abruptly quits on her first day, resulting in Nick winning a bet he made with Warrick.
- Catherine's relationship with Chris Bezich ends when she catches him with another woman.
- William Petersen as Gil Grissom
- Marg Helgenberger as Catherine Willows
- Gary Dourdan as Warrick Brown
- George Eads as Nick Stokes
- Jorja Fox as Sara Sidle
- Paul Guilfoyle as Jim Brass
- Eric Szmanda as Greg Sanders
- Robert David Hall as Dr. Al Robbins
- Nicholas Lea as Chris Bezich
- Jonathan Penner as Detective Travis
- Alex Carter as Detective Louis Vartann
- José Zúniga as Detective Chris Cavaliere
- Archie Kao as Archie Johnson
- Romy Rosemont as Jacqui Franco
- David Berman as David Phillips
- Wallace Langham as David Hodges
- Scott Klace as Carl Johnson
- Marina Black as Crystal
- Tony Amendola as Landlord
- Terrell Tilford as George Craven
- John L. Adams as Manny
- Bug Hall as Daniel Halburt
- Reiko Aylesworth as Chandra Moore
- French Stewart as Alien Minister
- J.C. Brandy as Nicole 'Raven' Richards
- Justin Kennedy as Lance Frazer
- Stacey Linde as Alien Wife
- Tony Mosti as Al Capone
- Vincent M. Ward as Space
- The song played at the very beginning of the episode is "Spitfire" by english electronic dance music group "The Prodigy "
- Jonathan Penner who portrayed "Detective Travis" would later become a three-time contestant on the reality show, Survivor.