LabVIEW - LabVIEW offers many of the functions you'd find in a traditional script-based programming language presented in a more intuitive visual interface ideal fo engineering.
itom - itom is an open source software suite for operating measurement systems, laboratory automation and...
PyLab_Works - PyLab_Works is a free and open source replacement for LabView + MatLab, written in pure Python.
Lawson Labs - Data acquisition support for Lawson Labs high resolution data acquisition hardware and systems.
SynthEdit - Visual programming software to build your own synthesizer.
proteus VSM - A virtual simulation environment for electronic circuits with support of digital and analog devices.