Air fluctuations indoors - detecting/measuring?

[floobydust]

You can easily detect a slight breeze with a thermistor.

Put enough current though it that it self-heats, and any convection cooling changes will lower its resistance.
Seen this used before on candle simulators and a motion-sensor for a halloween gag.

Using a 100 ohm PTC thermistor and 100 ohm resistor to 5VDC, its about 4% R change per degree, lots for an A/D to look at.