Another Star Trek nod: when Hardison is using the old computer with dial-up access, he refers to using "stone knives and bearskins."
In the Star Trek episode "City on the Edge of Forever", Kirk and Spock travel back into the past where Spock attempts to build a 23rd-century device using 20th century technology. When asked what he is doing, he says he is "endeavoring, ma'am, to construct a mnemonic memory circuit using stone knives and bearskins."
When Eliot has Hardison paged at Gate E to give him the gate badge, the announcer says "Paging Mr. Picard, Mr. Kirk Picard". Being a geek, Hardison recognizes the Star Trek reference (Kirk and Picard were captains of the Enterprise in Star Trek (1966) and Star Trek: The Next Generation (1987), respectively).
Another Star Trek reference... When Hardison enters the tower, he contacts Nate through the headset by calling for 'Leverage Flight 1701'. The registry number for the starship 'Enterprise' is NCC 1701.
When Parker is undressing to change clothing, Eliot throws his jacket toward the camera, blocking the viewer from seeing her disrobe further, breaking the fourth wall. This is similar to a scene in Buster Keaton's "One Week" where the camera operator covers the lens with his hand so The Bride can retrieve a bar of soap.
In the opening sequence, reference is made to the Emerald of the Caribbean. The island of Montserrat is known as the Emerald Isle of the Caribbean.