Use a bag such as this one to make your commute to work a bit easier. Black is just one of the colours you can pick from if you're going to buy this bag.
From Ryman
Targus 15.6 Inch Sagano Commuter Backpack in Grey, Grey
Technoworld PLC
Targus Sagano notebook case 39.6 cm (15.6") Backpack Black, Grey
This product is also available at 4 unverified merchants.