HALBERSTADT, Germany (AFP) - A new chord was scheduled to sound in the world's slowest and longest lasting concert that is taking a total 639 years to perform. The abandoned Buchardi church in Halberstadt, eastern Germany, is the venue for a mind-boggling 639-year-long performance of a piece of music by US experimental composer John Cage (1912-1992). Entitled "organ2/ASLSP" (or "As SLow aS Possible"), the performance began on September 5, 2001 and is scheduled to last until 2639. The first year and half of the performance was total silence, with the first chord -- G-sharp, B and G-sharp -- not sounding...