Get tricky with CMOS
By David Stonier-Gibson
This is a collection of slightly unusual things you can do with CMOS logic. Some of them are Not What The Maker Intended and some are simply pointing out some useful if little know chips. Not all are The Best Way of doing something, either. But if the chip you happen to have lying around can do the job now, it may be better than a trip to Jaycar or 4 week wait from eBay for the perfect chip.
Square wave oscillator
Crystal oscillator
Analogue multiplexer
Boolean function generator
3V to 5V level shifter