I downloaded this circuit from http://xkcd.com/730/

However, I would prefer to use an mbed in lieu of the arduino.

Has anyone attempted to build anything like this with mbed?

Yeah sure you can, but the problem is mbed is much more powerful so 90% of the circuit doesn't do any work anymore. It's not as impressive without all the whirring, buzzing and blinkenlights :(

Thanks Igor!

Since my days as an engineer at IBM, where I first saw it, I always post this sign above my work areas:

ACHTUNG!

ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!

DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.

IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.

ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.

Even though German is my native language and I speak English very well, I have trouble understanding it. Yet, most people seem to get the message.

Here are some more nice pics to place next to your mbed project