Home Automation over internet ( Control some applicances )
Crowd manangement ( RFID maybe, to track who has entered a certain room, who has left the room and the time, attendance tracking, not by swiping a card, but maybe a chip that tranmits a wireless signal )
I have say a soccer ball, and a goals, with a line across the goal mouth. I would like to have some setup where as i could tell when the entire ball crossed the line. Because for a goal to count the entire ball must cross the line, Thus elimating any arguments wether or not the whole ball crossed the line when there is a crowd of footballers around the goal mouth.
Lots of stupid ideas, nothing worth mentioning so i didnt add them to original post :-[
Put together an LED panel that represents a server environment. Have the Arduino send ping, http, ftp and other requests to each server every few seconds and wait for the reply. If there is none or in the case of http if you get anything other than 200 LED turns red. Then you got an at-a-glance over-all server room health check. All the LEDs are green... you're happy. Any turn red you got a problem.