Bicycle Mechanics - Noisy Crank

I have two bikes: '96 Cannondale F400 and an 02' Trek 7500.
Both of them seem to exhibit some sort of weird noise in the crank while pedaling. It's like a "click" once I get to a certain spot in the revolution. It happens on both bikes.
What's going on?
Thanks!

Is your crank hitting the tail of your front d.? Sometimes this is hard to see. I've also had the loose end of the front d. cable clip the crank arm ... again took an emberassing amount of time to figure out. Or, it could be that classic aluminum bottom bracket problem ... the only way to solve that is to take that baby apart once a month, clean it and lube the heck out of it.

I've had the clicking noise happen when a crankarm started to work a little loose.

Could be multiple problems. I actually had to different clicking noises coming from the same spot at once. The first click stopped when I tightened the click but the other creaking was there. I removed the cranks and BB all to relialize that I bent the BB and punctured a hole in it somehow. I replaced it to XT and all was good. Take it to your LBS and have them look at it.

Do you wear the same shoes riding both bikes? It could be the cleats making the noise if it happens on both bikes in the same pedal position.

As said it can be anything;

start with the pedals; check if they`re tight and no bearing play.
After that check your cranks the same way, if this is allright it must be either your BB or your crank hits something in the movement.