Yeah, during the first gas crisis gas got up to 30 cents a gallon. The lines for gas and even/odd days probably were worse than the price shock. But even with the ridiculous vehicles people are driving nowadays, the gas mileage they are getting is quite a bit better than back then, when an economy car might get low teens miles/gallon. It did kick off the bike boom though.
I just filled my car, a plug-in hybrid. $40 isn't much when the main concern is that it will go bad in the tank because it's not being used.
I'm sure a significant increase in gas prices will cause some to start cycling. It would be a good time for bike advocacy groups to give out lights/reflective gear