Vernor v. Autodesk, Inc.
621 F.3d 1102 (9th Cir. 2010)
The software that Vernor tried to sell on eBay, AutoCAD, is a widely used 2D and 3D design program. Vernor apparently sold this particular kind of software twice over eBay, and Autodesk tried to stop him both times.
EULAs continue to be the subject both consumer and legal controversy, especially over mandatory arbitration clauses and class-action waivers.