I worked for 18 months as a fire & rescue person at an airport. While it was a real airport (terminal building, check in desks etc) it was a small regional airport, and thus we typically had only 1 or 2 scheduled movements per day.

We had one ATC at the airport (they came and went in 3 month rotations). They were in the tower most of the time monday to friday (during normal office hours) and obviously there for all scheduled flights, day or night - but equally he didn't feel the need to hang around. Plus of course toilet excursions.

We had a traffic-control radio in our office, so we could hear the movements and (on weekends for example) issue a simple phrase like "good morning echo-foxtrot, this is xxxxxx, proceed with unmanned tower approach".

Our section was obviously manned 24/7 so in theory we could hear distress calls as well, but I don't think we ever did. One helicopter made an approach over the hangar, and landed on the hard-stand (not exactly what they're supposed to do) but apparently he'd pretty much run out of fuel. (According to the pilot he didn't turn the engine off after landing - he ran out of gas.)

Having a control tower doesn't mean much - on the Isle of Barra the airport does have a control tower but the runway is a beach:

http://www.youtube.com/watch?v=STqmbc8k9rU

There are also airplanes without radios (though such planes normally operate at untowered airports).

You'd be amazed where you're allowed to land a plane. Private grass field? Sure, but look out for rocks.