Following What is the most famous computer bug of all time?, what are the most famous concurrency-related bugs?
"Famous" means that the issue enjoyed coverage in mass media. Embarassingly costly issues, issues resulting in loss of life, or issues having an impact on politics are also considered.
"Concurrency-related" means that the issue was related to races, nondeterministic program outcome, or thread interaction in general.
E.g., the Therac-25 incidents and the Northeast Blackout of 2003 (@Kevin McKenzie: thx!) are famous and concurrency-related. But they are old, so, newer failures are appreciated.
There are some general famous-bug enumerations (e.g., http://en.wikipedia.org/wiki/List_of_software_bugs), but they are difficult to filter for concurrency issues.