Matt Damon's London street scene--showing Linus walking through London speaking on the phone--was shot while Matt Damon was in London filming "The Bourne Ultimatum". The Ocean's Thirteen production took advantage of this happy coincidence as they wanted the character Greco to be a British classmate of Roman Nagel. Thus Linus's being in London played well to the story.
Towards the end of the film, when Rusty and Danny are in the airport, they each mock each other. Rusty tells Danny to try and keep the weight off in between jobs next time. This is a reference to George Clooney, who put on extra weight for his role in Syriana (2005) and in turn injured his back doing some stunts. Danny tells Rusty, "Settle down and have a couple of kids," which is a reference to Brad Pitt and Angelina Jolie's relationship and children.
(@ 1:37:15) The numbers that "Mr. Weng" picks to win at the roulette wheel are 11, 12, and 13--a reference to the three "Ocean's Trilogy" titles.
The phrase "Billy Martin" that Danny mentions to Willy Bank during Reuben's hospitalization is gambling slang for "a second chance." The phrase refers to famed Major League Baseball manager, Billy Martin. Despite his talents as a manager (he led the New York Yankees to two World Series titles), Martin's fiery temper, fueled by his alcoholism, often got him into trouble and, as a result, he was fired multiple times. Despite his character flaws, Billy Martin was always being given "a second chance."
The special scent that Linus puts on his neck to seduce Abigail is noted in a title card as "The Gilroy." This is an in-joke on Tony Gilroy who wrote the screenplays for The Bourne Identity (2002), The Bourne Supremacy (2004), and The Bourne Ultimatum (2007), all starring Matt Damon. Gilroy also wrote and directed Michael Clayton (2007), which stars George Clooney and is produced by Steven Soderbergh.