The Boomtube (aka, the Stowaway Boomtube H201 Portable Speaker System) by Think Outside is designed to work with nearly any portable music source, including personal MP3 players (read: iPods), Cellular MP3 phones, and laptops.
The anodized aluminum Boomtube comes shaped like, duh, a tube (great for fitting into backpacks, briefcases, and so forth). To use the system, just twist off each end: each end becomes a two-inch speaker, and what remains is a subwoofer-like bass tube.
Costs $199.99 (and you get free shipping until January 31st).
Source: The Gadget Blog.