When Dinozzo walks into the hospital, the interns are talking about the time it takes to receive test results. One of them comments "Dr. House receives his results in ten minutes." This refers to the lead character in the TV show House (2004)
In one scene, Abby asks McGee "what was that movie where they took the whole car apart, searching for heroin". McGee doesn't know and says he "is not Tony." That movie is The French Connection (1971).
The disguise that Anthony DiNozzo, played by Michael Weatherly, wears outside the restaurant singing is the Logan Cale character he portrayed in Dark Angel (2000), albeit the hair is a little longer.