Rocki ($49) is a small adapter that turns old speakers into a wireless sound system that you can control with a smartphone, tablet or computer.
Plug the device into the speaker auxiliary input via 3.5mm or RCA, connect the Rocki and smart device to your home WiFi network and you can start streaming your music. The device, which was created thanks to a successful Kickstarter campaign, is available for purchase now through the Rocki site.