iTour-Pop Portable Rechargeable Speaker for iPod, Sansa, Zune, iPhone 5, 4S, 4, 3GS, 3G, BlackBerry, HTC EVO, DROID, Samsung Galaxy S3, 2, LG Optimus G, and more (Color Option: Black)
This is the perfect size for the office or any other place where a more traditional speaker is too large.  The sound coming from this little thing is terrific; great bass which the I-pod seems to be missing!  It's definitely going to be on my packing list from now also on so I can enjoy my music when I travel.