Raspberry pi is a credit-card sized computer that can plugin into your TV and keyboards. It is a capable little PC which can be used for many things that your desktop pc does.
Offical website:
OS:
If you are fresh man, it's better to read the FAQ list. That's very useful for you.
My external devices:
- HDMI to HDMI lead
- SD card class4 4G
- Power adapter 5A/1A+, 2A better.
- USB hub
- USB mouse
- USB keyborad
- USB wireless network card