FSF v. Cisco
The Free Software Foundation's first lawsuit, filed in 2008 over GPL code in Linksys routers and settled a year later with a new job title at Cisco.
When Cisco bought Linksys in 2003 it also bought a product line packed with GNU software: GCC, glibc, coreutils and more. From 2003 onwards the FSF kept pointing out missing source code, product after product, and Cisco kept fixing each case without ever fixing the process. In December 2008 the FSF filed suit in New York, the first in its history.
The May 2009 settlement was more about plumbing than money. Cisco had to appoint a Free Software Director for Linksys, tell past customers about their rights, publish the source and make an undisclosed donation to the FSF. It set the pattern for how GPL disputes tend to end: nobody really wants the cash, everybody wants a compliance process.