1. Control a robot
In a move straight out of a saturday morning cartoon show, kids can now use their video game toys to control robots! Not giant robots (or at least, not yet, but we're sure Japan is working on it) but cute little mobile robotics platforms like the Pekee. If you want to get a glimpse of the future, replace "robotics" with "weapons", and "games" with "future death sports" where your high score is measured in collateral damage (and you only get one life).
2. Run quake
Nintendo takes a lot of stick over recycling old titles for easy money. This compressed Quake doesn't fall foul of that crime because
a) It's been developed utterly free of charge by fans
b) It's Quake!
Quake is a key part of first-person-shooter history, and the fact we can shrink what used to take a desktop PC into a handheld console is a testament to how awesome this future we're living in is. The only problem with this port is that network play isn't yet working, and that was kinda-sorta the whole point with Quake, but it's in the works so get ready to unleash Quad Damage wifi destruction.
3. VOIP phone
It's got a mic, speakers and a wireless connection - the only reason your DS isn't already the coolest phone in the world is Nintendo are too slow at development (nothing has been heard of the official "DSpeak" application since 2005). Luckily, many have taken the code into their own hands, writing their own >voice-over-IP software for the handheld for no other reason than it'll be awesome. Let's face it: a phone that can also play DS games would make Star Trek communicators look shoddy.
4. Barcode scanner
Games are a great way to live out your dreams of being a secret agent, a racer, or even God. I wasn't aware anyone fantasised about being a supermarket checkout monkey, but apparently Capcom think they do. They've built a barcode reader - a bulky add on that lets your diminutive dual-screen double in size and scan codes. Of course it's all part of a cunning plan to empty your wallet - the idea being that you buy cards with powerups that can be read into the machine to help in certain games. Note that this translates as "paying for something that will let you pay to play games that you have, in fact, already paid for." If this doesn't trigger mass riots on launch we can only conclude that capitalism works a bit too well.
5. DS Linux browser
Linux on a DS. This shouldn't really surprise you - there's a small but fearsomely dedicated squad of nerds committed to getting Linux running on every electronic system on Earth. And by committed, I mean they make Captain America look like an unemployed hippy. Show a team of linux developers a toaster with three lines of code, and they'll work night and day to prove that two lines of linux works just as well and far more efficiently. Sure, you might have to wait a year or two for someone to write "bread-warming" drivers to get your actual breakfast, but by god they've shown Redmond they don't have the monopoly on breakfast-heating technology.