This page at Cambridge University says its a myth. There is a burst of energy when you turn them on, but its equivalent to 2 seconds of run time. Also the light lifetime is not seriously affected by turning it off and then on again occasionally.
The energy consumed to start a typical lamp is the equivalent of 2 seconds running time, so it is wrong to say it takes a lot of power to start them. It is true there is a current surge but this takes place in less than one-eighth of a second and because it happens so quickly it takes very little energy.
The Mythbusters performed a practical experiment to measure the amount of power required to turn on various lights compared to their steady-state consumption when on. They found the following:
Based on the amount of energy consumed turning on the bulb, they were able calculated how long the bulb would have to be turned off in order to make it worth the energy savings, i.e. “It’s best to turn off the bulb if you are leaving the room for”:
In other words, its almost always best to turn the bulb off. Even the 23 seconds for the fluorescent lights isn’t very long, and the rest of the times are pretty much blinks of an eye.
It is true that switching on/off fluorescents reduces lamp life but lamps are designed to be switched on/off up to seven times a day without any effect on their life. How many times a day do your colleagues switch on/off to save energy? Probably not enough times to reduce the lamp life.
Addressing the last part of the question is harder.
Is there any light source that was in popular use 15 years ago that uses more energy to be turned off and on that leaving it on for 30 minutes?
At risk of doing some Own Research, some back of the envelope calculations suggest that this is unlikely. A typical 4 foot flourescent tube consumes 36 watts, and a light fitting will often contain two tubes, making a total steady-state power consumption of 72 watts. If the starting process takes 5 seconds then to take as much energy in those 5 seconds as it takes during 30 minutes of continuous operation the light fitting would have to draw 72x30x60/5 watts, which is about 26kW. At the UK standard of 240 volts that would be 108 amps, or about 8 times the power of an electric kettle. For US 110 volt circuits it would require 236 amps. However flourescent lights have never required any special cabling to deal with such high currents.