‘You, over there. You’re an “S.” ‘ (Photos by Scott Harrison | Retna)

Yesterday saw the bikini-wearing masses descend on Planet Hollywood Resort for the Cosmopolitan Bikini Bash 2010 with Mario Lopez. Not that he was in a bikini, we mean. He was just there. Fortunately. We might not stand for much, but we’re throwing down with the Mario-Lopez-in-a-Bikini-Averse camp.

Lo Bosworth of The Hills and Holly Madison made the rounds as well, as dozens of girls held up blue lights to spell out “Cosmo” on the P-Ho’s pool deck. The pic will run in the August issue of Cosmo. Lopez was hawking his diet book, Extra Lean while Bosworth wandered around in a sheer robe. Get it? “Extra” lean? Because he’s on that show. Saved by the Bell.

By Jason Scavone

Their fallback plan was the fat kid from Head of the Class. (Photos by Scott Harrison | Retna)

Mario Lopez spoke to a crowd at Rave Theater at Town Square during the Actors Expo about breaking into the business, hosting your own show and how to duck calls from Lark Vorhies. We didn’t really put it all together until this appearance, but Lopez has the same smile plastered on his face no matter what he’s doing. Look at him. Look at him drinking from that bottle of water. He’s still smiling. It’s kind of creepy the way clowns are creepy and they have that blank, unchanging expression even though you’re sure there’s a pretty good chance at least one teenage runaway is buried under the back porch. All we’re saying is have some sort of public fit of rage, Mario. It’ll make us feel better.

By Jason Scavone

All this can be yours in the exciting world of acting. (Photo by Isaac Brekken | Getty Images)

Quick! Pick your dream acting coach. Robert De Niro? Are you kidding? De Niro has better crap to do. Daniel Day Lewis? Are you out of your mind? That guy is crazy. If his next movie is about going to prison (again), there’s like a 60 percent chance he’ll shank you. Greatest-living-actor Peter O’Toole? The guy is like 140 years old and the strain of teaching acting may be the thing that finally snaps his brittle bones. Also, he’s probably drunk right now.

Look, we’ll make this easy on you. You’re going to settle for Mario Lopez. He’s the keynote speaker at the Actors Expo Sunday at 3 p.m. at Rave Motion Pictures, that’ll help you get the ins and outs on how to get your career going. Step one? Distance yourself professionally from Dustin Diamond as far as you can possibly go. It’s $20 if you sign up by Saturday at ActorsExpo.net or $30 if you wait ’til the day-of.

By Jason Scavone

Only four chicks? You’re slipping, Mario. (Photos by Erik Kabik | Retna)

The We Are All One Step Closer to the Grave Train keeps on rollin’, this time firing the steam whistle of our impending doom with Mario Lopez’s 36th birthday, even though he lives on as perpetually 18 and in parachute pants in our hearts.

Lopez hit The Bank at Bellagio Friday night with girlfriend Courtney Mazza, sister Marissa, cousin Daniel DeSanto and Aubrey O’Day where he was hosting. Eventually, Lopez turned up at Rain inside the Palms with a crew of 12.

Earlier Friday, Al B. Sure was spotted at Ditch Friday while DJ Tiesto and six friends headed up the Playboy Club.

Lopez continued his birthday celebration Saturday night with dinner for 14, including George Maloof, at N9NE Steakhouse. Debbie Allen had dinner there as well, while Eddie Cibrian sat at the bar for drinks. Gordie Howe, who still could probably put on skates for like the Panthers, had dinner with 14 friends. Golfer Natalie Gulbis, who, to be fair, could probably also play for the Panthers (they’re kind of terrible) dined with some girlfriends.

Pete Rose, who could not only play for the Panthers but would probably lead the league in penalty minutes, was at Nove Italiano for a friend’s bachelor party. That night, DJ Armin van Buuren spun at Rain.

By Jason Scavone

‘Hey baby. Who wants to make out with A.C. Slater?’ (Photos by Scott Harrison | Retana)

Azure pool at Palazzo was christened Saturday by Mario Lopez, who was joined by Melora Hardin of The Office and Nadine Velazquez of the now-canceled My Name is Earl. The pool is a new concept — zigging when all of the club pools zag. It’s got spa services, food by Wolfgang Puck and fashion shows every Saturday. Which explains why Mario Lopez was wearing that charming little Dior dress.

By Jason Scavone