When the last d20 is rolled, and Tiamat's dying scream shakes the cavern walls, only two things remain: the distribution of experience points to the party, and loot. Your party's dwarf fighter, and that human paladin might be able to lug piles of gold and platinum, but your little gnome mage can't quite heft that much stuff. What to do?
The chaotic neutral halfling thief offered to carry a portion of your loot, but do you really trust "Shifty McFingers" with your well-earned booty, or can you find another way to carry it all? Luckily, amidst the ponderous piles of platinum lying about the place is a simple nondescript bag that everyone overlooked - except you, of course. Peering into the bag, you see nothingness - an almost infinite depth in which you can place way more loot than your entire party combined! While the rest of your party is trudging away with a backbreaking mass of booty, you're happily plundering ton after ton of coins, and casually flinging your new bag over your shoulder.
While transdimensional space is, as yet, impossible in this plane of existence (Doctor Who fans, keep quiet for now), ThinkGeek Labs has developed our own messenger bag that comfortably carries way more than a bag of its size normally could! It's big enough to carry a 17" laptop, Large 3-ring binder, two college textbooks, two paperback books, Amazon Kindle, iPod, cellphone, cables, pencils, business cards, spare batteries... I could go on and on.