OK, here's mine:
I was hired a couple years ago by a company that makes Mosquito traps for
Entomologists.
These traps have a light and/or CO2 source to attract Mosquito's, and a bag
with a fan
in front of it to blow the Mosquitoes into the bag where they die and
dehydrate for study later.

Problem is these traps sit out in fields far from power sources so battery
life is an issue.

I used a '73 to control the trap. A CDS cell measured light, they only come
out after dark,
and then only for about 4 hours. A thermistor to measure temperature, they
only come out above
50F. The PIC would start flashing a little incandesanct light at dark above
50F, open the bag
door (solenoid) start the fan, and optionally start puffing out CO2 from a
small solenoid valve
and tank. After 4 hours, if so programmed, the whole thing shut down to
conserve battery power for
the next day. Door closed, CO2 stopped, light stopped, fan stopped etc....
Flash rates, puffing rates and a bunch of other options were all programmed
from a
8 pos-DIP switch. Worked great from what I hear....

thanks for listening....

Jason Wolfson