Sure, trained waiters can carry half a dozen cups of beer for delivery to your table without breaking a sweat. Try doing the same when refilling from the keg in the kitchen all the way to the living room, though, and you'll realize just how tough it can get. Not quite the case with the Stack-Cup, which you can stack via the handle for easy handling even when full.
Instead of trying to balance half a dozen cups filled to the brim across your arms, all you have to do is layer them in a spiral pattern, with one on top of the other. In theory, there should be no limit to the number of cups you can stack using this method, although the product page says the current record sits at 25 cups without causing the whole thing to crash down.
The Stack-Cup is a durable plastic glass that can hold 500ml of beverage each. It looks ordinary enough until you notice the odd-looking handle, which uses a patented design that allows it to stack while maintaining balance even when the cups are fat with content. Since it's plastic, the caps are reusable and can be machine-washed up to 1,000 times before showing signs of wilting.
Firebox has the Stack-Cup available in sets of 6, priced at £12.99.