Again assuming Phalenopsis, I've found something similar to Al suggested.
Over the winter I keep my Phals on a window ledge over a radiator BUT the radiators are turned off all night. This means that over the winter the Phals get cold during the night but are kept quite warn during the day.
The treatment seems to have prompted them to flower each spring.
I didn't do this purposfully at first, it was just the most convinient place to keep them and I knew little about them. But I later heard that having a larger difference between night and day temperature could prompt phals to produce a new flower spike.