I am building a weather station using several Arduinos . It will gather information from various sensors and send it back to the base station via a 433MHz wireless connection. The base station will display the data on an LCD and send it to my server over ethernet where it will be stored in a mySQL database. A web interface written in PHP will then be able to show real time data as well as display charts.
I am still waiting on the rest of the parts to come in the mail, but I got my first sensor yesterday, a Bosch BMP085 digital pressure sensor. I ran it all day and gathered the temperature of my computer desk as well as the barometric pressure. I loaded the data into an openoffice spreadsheet and made a chart of it. I doubt you are interested, but here is the raw data it collected.
Click For PDF Chart
My Gizmos & Widgetry 