Using a wireless router, an old boom box, and a sound card, you can stream music from your computer to a boom box or any other audio device. Configure OpenWRT (Linux for embedded divcces) and imagine taking Pandora with you on the go. The creator decided to use the Netgear WGT634U wireless router specifically because it comes with a built in USB port.
The plan: “I plan to make a wireless, portable internet boombox from a bunch of
parts I scrounged up/have had lying around my house for a while.” The project is in early stages of development, but the description and proof of concept are worth the read.