Today marks the 200th anniversary of the Supreme Court’s landmark decision in Marbury v. Madison, in which Chief Justice Marshall famously announced the doctrine of judicial review. In honor of the event, the Washington Post offers an article here discussing the opinion. Students in my class have heard too much about this case, but will recognize the WaPo article as advocating a "strong" form reading of Marbury as an aggressive check on the other branches. For those who haven’t read the case before, the decision is available here. (Thanks to Howard Bashman of How Appealing for bringing this story to my attention.
Now to the contest. Everyone knows that Marbury was the first time that the Supreme Court exercised judicial review, right? Wrong. The Supreme Court used the power of judicial review to strike down a state law in one case preceding Marbury, and while expressly reserving the question of its power to do so, had reviewed the constitutionality of a federal statute in another. (Careful readers will note that circuits courts also exercised this power, but I’m looking for Supreme Court cases.) The first reader to name one of the two Supreme Court cases wins a No Left Turns Mug. 
(Hint: I’m not looking for a dissenting or separate opinion.)
Bayard v. Singleton (1787)
Hayburn’s Case, 2 U.S. (2 Dall.) 409 (C.C.D. Pa. 1792) (holding that Congress could not give the Secretary of War power to review a judicial determination)
See also Maeva Marcus, Judicial Review in the Early Republic, in Launching the "Extended Republic": The Federalist Era 25, 28, 36-48 (Ronald Hoffman & Peter J. Albert eds., 1996) (discussing pre-Marbury assertions of the power of judicial review, by Justices of the Supreme Court (riding circuit) and by state court judges)
See generally Maeva Marcus, Hayburn’s Case: A Misinterpretation of Precedent, 1988 Wis. L. Rev. 527
Mickey: Bayard (1787) would not be eligible because it was not issued by this Supreme Court--that is, the Supreme Court as established by the Constitution of 1789.
Um.. would that be ?Exparte Chandler andUnited States v. Yale Todd
A state act was deemed to violate a treaty and thus declared unconstitutional in Ware v. Hylton (1796). Marbury was the first instance where the Supreme Court declared an act of Congress to be in violation of the constitution.