Time on UNIX like machines (including Linux) is counted in seconds since midnight January 1st 1970, the moment when time began on the Unix operating system (aka the Unix Epoch).
Today at 00:31:30 CET (23:31:30 UTC) counter showed magnificent number 1234567890 (that happens once in an epoch !) and many hearts of the right geeks have been pleased ;) Congratulations.
Celebrations have taken on many places around the world. Sometimes its the little things I enjoy.