Hi Ray,
firstly congratulations on OpenSprinkler – great system. I too would like to selectively ignore rain delay on certain stations. In addition to the scenarios others have outlined here, I have a further relevant scenario. My watering system has several water tanks involved. When it rains and my main tank fills, I open a solenoid/value via OpenSprinkler to pump water up to my larger storage tank. It would be great to rain delay most, but not all stations, selectively.