Linutop

Computer are getting smaller in size. If you have seen Asus EE or any other small devices PCs, then you should also see Linutop. Here's some overview from the official site:

Overview

Linutop is a ready-to-use small computer, designed to reduce maintenance costs.

Low maintenance

The Linutop operating system is stored on an internal flash memory and cannot be altered by virus or mishap.

Initial state can be recovered at each restart.

Low deployment costs

Linutop is delivered with free standard ready-to-use Linux software: Firefox, Open Office, VLC Media player... and can be easily customized with additional software.

Energy saving

With no moving parts, Linutop offers a completely silent (0 dB), energy-efficient operation in an extremely small package

There's a list of products on their shop. I guess the most suitable for Internet Cafe is Linutop 2, which has this specs:
- 512 MB RAM
- 1GB internal memory
- OS Linutop2.2 preinstalled (based on Ubuntu)
- Power : 8W (US compatible AC adapter)
- Weight :580gr 20oz
- Price: EUR 280

Unfortunately, the shipping cost to Indonesia is quite expensive (EUR 150). It's more than 50% of the Linutop 2 price. It would be beneficial if you bought lots of them.

You can just plug it on the back of your LCD monitor and it will work just fine. Also, it's very portable, because you can unplug it anytime and bring it on your backpack.