How can I use both my external speakers and laptop speakers at the same time?

How can I use both my external speakers and laptop speakers at the same time?

is this possible. I think it would be kind of cool.

 

Apart from sounding like pure crap, you'd have to open the system and cut the pin that tells the PC there's a headphone in there, voiding your warrenty and being quite risky, and inconvenient in the future.