Many FORTRAN programs over my physics years: 

• milisecond analysis of pulsar data
• retrieval and archive of data from tape (md -> FORTRAN)
• FORTRAN and C computions
• FFT
• electron cloud computations in multiwire high-energy-physics detection system
• PGPLOT to PHPLOT

In 1993-94 my adviser asked me to run the theoretical component of the experiments our group was running in plasma chambers. He asked me to use his VisualBasic code because that way he could understand it. However, in order to do dust-plasma simulations you need to run many-body simulations and with the current code I calculated it would take a few years to generate enough data to complete my thesis. Fortunately, at the time, I was also the network/workstation administrator for the astronomy labs which had 40+ workstations networked via TCP/IP.