audrinapool3.jpgaudrianvegas8.jpgcourtesy of WireImage

Before partying it up in Hollywood, Audrina Patridge celebrated her 25th birthday at the Liquid Pool Lounge at the Aria Resort & Casino in Las Vegas, and the Hills hottie was accompanied by her boyfriend Ryan Cabrera as she splashed around and munched on a delicious custom cake. Naturally the lovebirds got into a food fight, and even though Ryan kept his luscious locks covered with a hat when he jumped in the pool, Audrina had a great deal of fun squirting her fellow partygoers with a giant Super Soaker. HOT!