Yes it can , it requires external hardware like 3 or 6 axis gyro and accelerometer. If it's something you are interested in , then order yourself a kit we have a couple people who have scratch made a balance bot but we ( xlrobots) do plan to start 3d printing a balance bot in the near future. It's one of the robot designs on our list over the next few months. We jump on whatever the community wants and is willing to $ for

There are a few balance bots in the robot showcase

The biggest problem will be the speed at which the sensor is read and the servos/drive motors are updated. In some cases you may find the EZ-B may not be fast enough (speaking of the V3 board, not a clue if the V4 is capable yet).

I think most of the balance bots hand off the work of actually staying in balance to an Arduino or other board that can react quickly without communicating with the PC, and use the EZ-B for giving movement and interaction type orders.
The V4 and a fast PC may be fast enough to respond to the sensors and keep a bot balanced, but given how other PC tasks can sometimes bog down applications, I wouldn't trust it unless the bot can sustain a fall and stand itself back up.

Alan

This could be something else which can use the whole "control and Arduino via an EZ-B" thing that has been mentioned and which I am working on using for my 6 foot android. While my plans are more for stabilising by controlling the legs at all times with commands for moving them sent from the EZ-B I'm sure similar could be applied to have an ATTiny or similar PIC deal with stabilisation of the balance bot while also waiting for movement commands.