Although electric typewriters have made original examples somewhat obsolete, if you have one and some spare time and money it can be a lot of fun to experiment with automating the typing. This has been demonstrated by Harvey Moon who uses an Arduino Mega board (as it has plenty of I/O) to control forty car door lock actuators via relays. These are used to pull a wire connected to each typewriter key - and thus "type".
Certainly something different that has been achieved with an Arduino. For more on this and some other artistic Arduino-based projects, visit the creators interesting website. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're looking to control relays and other higher-current devices - it's much easier to use dedicated relay control boards. Here at Freetronics we have the RELAY4: board, perfect for controlling up to four relays with Arduino (or any other microcontroller's) digital output pins:
Or if you'd like to control up to eight relays - or more at once with an Arduino Uno or compatible board - consider our RELAY8: board. Controlled via I2C, you can stack up to eight shields with the appropriate power supply to support 64 relays at once: