Freenode:
##c
##electronics
##workingset - low traffic but good place to experiment with people's workflow
#ada
#arduino
#avr
#compsoc-uk , if you're a UK CompSci student you should be here
#debian
#furnace
#python & #python-scotland
#ovh
#systemd
#vim
#vmware
I have more but they are increasingly less accessible. If you need to ask for them, you don't belong :^)
