T1A
T1B Accidental shoot-down of Iran Air Flight 655 (Airbus 320)
T1C FBI Virtual Case Files
T1D Queensland Health payroll debacle
T1E Y2K
T1F 
T2A Virgin Blue reservation system crash
T2B New Zealand INCIS (1990 - 1999)
T2C Sony BMG copy protection rootkit scandal
T2D TJ MAXX Marshalls WEP security breach
T2E LA Airport ATC (lost contact with 400 planes), 2004
T2F Mars Polar Lander
T3A Mars Rover Spirit flash memory anomaly
T3B UK Organ Donor Register
T3C Soviet retaliation against the United States by detecting a satellite error (1983)
T3D McAfee antivirus deleting svchost.exe from Windows XP
T3E
T3F Sydney Water's Customer Information and Billing System
T3G Mariner I space probe