The case currently pending before the United States District Court for the Northern District of Ohio (Judge David Dowd) is U.S. Citizens Ass'n v. Sebelius. Back in November, Judge Dowd granted the United States's motion to dismiss some of the plaintiffs' claims, but it denied the motion with respect to the claim that minimum essential coverage requirement exceeds Congress's enumerated powers.
In January, the parties filed their motions for summary judgment. And on Monday, they each filed their respective memoranda in opposition to the other's motion for summary judgment. You can access the memorandum filed by the U.S. Citizens Association et al. here, and you can access the United States's memorandum here.