A cheap and easy instructable that is fun too.
Step 1: Materials
The materials are:
9-volt battery holder
Small DC motor
Hot glue stick
Step 2: Wiring
Attach the two negative leads with each other and same for the positive. You can do this by either soldering or binding the wires together.
Step 3: Vibration Motor
In this step you take the hot glue stick a cut it so it is one inch long. Then you stick it on the motors shaft as shown in in the photo.
Step 4: Attaching the Circuit to the Pen
Attach the pen to the motor using the rubber bands like in the picture.
Step 5: Power
Place the in its holder you are done. have fun and write away.