Here's the plot summary for The House Bunny:
When Shelly, a Playboy bunny, is tossed out of the mansion, she has nowhere to go. But then she falls in with the sorority girls from Zeta Alpha Zeta. The members of the sorority are about to lose their residence. They need a dose of what only the eternally bubbly Shelley can provide... but they will each learn on their own to stop pretending to be what others want them to be and start being themselves.