Other than your own feet, the best, safest and most affordable way to move around in central Athens, by far, is by Metro.
Athens Night Segway Tour
Athens Segway Tours
The Segway is a self-balancing, personal transportation device designed to go anywhere people do. It is not a motor bike and it is not a bike. You can go fast on pedestrian areas and is efficient for the street areas. Easy to use and operate, the two-wheeled Segway has 5 gyroscopes that monitor your balance 100 times a second and automatically respond to your body's movements. The rider glides smoothly as the Segway senses where you want to go. It runs on batteries that can last up to approx. 35 Km. and can go as fast as 20 Km/hr.