The Girls Next Door

The sixth season begins with Hef's new girlfriends Crystal Harris and twins Karissa and Kristina Shannon. The sisters travel to Las Vegas to celebrate their double Playmate issue.

Hef and Crystal go to Las Vegas to join the twins. Later, they go to see Holly in a live show.

Crystal, Karissa and Kristina get into trouble on a Hollywood tour bus and fear they may be arrested.

The twins and Crystal camp in the backyard at the mansion with some friends, but end up in Hef's room to watch a movie.

Karissa and Kristina prepare for roles as sexy twins in Sofia Coppola's movie "Somewhere." Meanwhile, Crystal learns she will be a Playmate and poses for her photo shoot.

Hef attends a music festival in Italy and takes the twins and Crystal along to share the fun.

Bridget Marquardt hosts a fashion show to benefit an animal charity and gets Crystal and the twins to help out.

A film shoot for a video game takes place at the mansion. Also: Crystal takes singing lessons.

Holly, Bridget, Crystal and the twins throw a baby shower for Kendra.

Hef and Crystal celebrate their first anniversary of being together.