A boombox your laptop is not, and speakers that are both portable and powerful are hard to come by. Depending on your needs, Logitech's Z305, a 360 degree sound bar, and Z515, a 50' wireless speaker, might do the trick.
The tubular $99.99 Z305 powers by USB and clings to the top of your laptop, while the $60 Z515 includes a USB dongle and a single speaker that can play for 10 hours over 2.4 GHz wireless up to 50 feet away from the laptop mothership.
Both speakers will be available later this month, so start legally downloading music right now! [Logitech]