2000 town and country trouble starting. sometimes is starts on the first try, other times it takes several tries and it will click once, then nothing. we cleaned the battery terminals and actually replaced one of the clamps, it seemed to fix the problem for a day or two

Use a gage and check proper fuel pressure. Cycling the key on and off several times before you crank it, allows the fuel pump to prime the system.
How long since a tune-up? Are there any applicable trouble codes?

crank sensor will do this along with a few other things , get the OBD codes read

Try rotating the steering wheel; it may be inline with one of the locks.

If security light is on and the vehicle will not start, then you need to find out the trouble code that set and turned on the security system.You can try locking and unlocking the doors with the key to see if the system will reset.

yes it sounds like the starter is bad,you have to keep on turning the key and you hear a click everytime you turn the key,replace the starter that should solve that problem,also make sure your battery connections are tight and clean.

I don't have a solution, but my 2000 town and country does the same thing. I just bought it a month ago and it started about a week after I bought it. I took it to my mechanic and he said the starter post were dirty and cleaned them, said that should fix it. Needless to say it's still doing it. I would love to know the reason as well. Anyone have any suggestions.

Check the oil level. The low oil sensor will disable the ignition if more than a quart low. If you have not checked your oil in the last 1600 miles, its past time to do so. Check oil often.

You have a bare wire that is rubbing. Take to your local dealership.

We had the same problem. It was the circuit board in the dash. There were crackes in one of the solder spots. My mechanic removed the dash and did a spot solder on the place with the cracks. It has worked for two months. It seems the solder spot was with a too cool of a solder when it was manufactured. Do it yourself or get your mechanic to fix the probem.

Did you try inserting the key in the drivers side door and locking and unlocking it manually several times to reset the alarm system. This was the problem with my 1996 Chrysler Town & Country LXI