"Year 2000 Bug"
1) A software bug caused by the use of 2-digit numbers to represent the 20th century year. When the date became 2000, some software thought it was actually 1900 (or some other incorrect date).
2) A bunch of bullcrap made up by paranoid doom-saying wackos and the computer-ignorant media.
1) I have to fix the Y2K bug in this old Cobol program.
2) When the Y2K bug hits, planes are going to be dropping out of the sky!