Very easy solution in Tel Aviv (Israel) (Score 1)

I've just visited family in Tel Aviv. Here;s how it works there:
1. Pre-pay and register with the city
2. Park your car
3. Call/SMS a predefined number with your car license plate (I guess there's also a web interface).
4. Go. do stuff. come back.
5. Repeat step 3.
6. Drive away.
It's that simple. My brother (who lives in Tel Aviv) loves it.
Easy. Simple. Works.