08/21/2012 at 02:30 PM EDT
There wasn't a dull moment over the weekend for Ryan Lochte.
Lochte, who has been partying
in Sin City since Thursday, was sure to cover all of his bases.
On Sunday, the athlete enjoyed an extended birthday dinner at Bacio Italian restaurant inside the Tropicana Las Vegas with a large group of guys, including fellow Team USA swimmers Cullen Jones and Conor Dwyer.
"Ryan sat on the outside of the restaurant, where women walking by went crazy over him, screaming and waving," an onlooker tells PEOPLE. "They were snapping photos."
Lochte – who munched on salad, pasta, sea bass and salmon – was brought a special Olympic-themed cake at the end of the meal, which he Tweeted
about, that even included his signature term, "Jeah." (Lochte turned 28 on August 3.)
After dinner, Lochte closed out the weekend with a trip to XS nightclub inside Encore for the venue's Sunday Nightswim party.
"Ryan hung out in the deejay booth" with duo Manufactured Superstars, an observer tells PEOPLE, adding that the fully clothed Olympic swimmer was not dressed in his usual pool attire
. "He was a good sport in posing for photos with groups of ladies, and stayed at the party late into the morning." – Melody Chiu and Jennifer Garcia