From Wikipedia, details of an event I remember clearly: "In 1975, NBC unveiled a new logo that was identical to the Nebraska [public television network] logo, but for the blue coloring of the right trapezoid in the NBC logo. The [Nebraska] commission sued NBC for trademark infringement, a suit which generated national attention. In an out-of-court settlement, NBC donated a color mobile unit and other equipment totaling over $800,000. NBC paid an additional $55,000 to reimburse the commission for the costs of eliminating the old logo from all advertising..."

And that doesn't count what NBC paid someone in the first place to come up with the same logo that the Nebraska network was using.