We'll use the Node version of Wiki to experiment with very small and very interactive servers.
Node Access to GPIO where we explore how we might be talking to things.
Peaberry Development with David Turnbull.
About Twadio Plugin special purpose SDR application.
About Txtzyme Plugin talking to whatever we happen to have connected.
Tricolor LED Strip from RadioShack
Waterproof Sensors with familiar chips.
Resources
The Pi makes an nice little server easily placed next to devices that source or sink information.
The wiSticky 
is the size of a credit card and about three times as thick. Thickness comes from layering an e-ink display with battery, circuit board and a refrigerator magnet used to stick the board where it will be seen.
Notes by Bauwe Bijl regarding his RPI type B v.2.0, HD: 8gb sd (class 10) with Raspbian "Wheezy"