I've never had the privilege or the pleasure of arguing before the U.S. Supreme Court. I did "appear" once in the U.S. Supreme Court, in the entirely pathetic sense of having set foot in the courtroom during a tour.
Maybe I can claim a "virtual appearance" in American Needle v. NFL, which the court heard last month.
The NCAA cited my law review article in its amicus brief in support of the NFL's claim it is a "single entity" incapable of conspiring with itself in violation of the Sherman Act, Section 1 (i.e., the NFL is immunized by the Copperweld doctrine).
You can find my article, "Take Us Back to the Ball Game: The Laws and Policies of Professional Sports Ticket Prices," on Westlaw or SSRN. The abstract is here.
The NCAA found helpful my review of the evolution of various pro leagues:
"Many current major American sports leagues are composed of members who at one time were members of different, competing leagues. The current NFL has teams who were, at one time, members of the competing American Football League; the current NBA has teams who were, at one time, members of the competing American Basketball Association; the current NHL has teams who were, at one time, members of the competing World Hockey Association; and the NCAA regularly admits member institutions who previously had been members of other sporting associations, such as the National Association of Intercollegiate Athletics. Nathan Scott, Take Us Back to the Ball Game: The Laws and Policy of Professional Sports Ticket Prices, 39 U. Mich. J.L. Reform 37, 53-55 (2005) (recounting histories of the NBA and American Basketball Association, NHL and World Hockey Association, and the NFL and the American Football League); . . . ."