Water-powered clocks, eye-controlled arcade games and pole-dancing robots: this year's CeBIT tech fair, the world's biggest, showcased gadgets ranging from the useful to the downright nerdy.

Can't be without your tablet computer or smartphone even when nature calls? Dutch company "phoneclip" has pioneered a small but strong device that can attach your beloved iPad to any vertical surface -- including the toilet wall.

Yours for around 20 euros ($25), the clip can also be used to stick your smartphone to your bike handlebars, car dashboard or steering wheel, supermarket shopping trolley or even sportswear, explained entrepreneur Hugo Passchier.

Back after a year's absence, German firm getDigital showcased their latest range of -- in their words -- "nerd toys" that no self-respecting geek should be without.

For fans of sci-fi classics, getDigital offers the must-have pizza cutter or bottle opener in the shape of the Starship Enterprise from Star Trek or the machine that makes ice cubes in the form of R2D2, the stubby robot from Star Wars.

And for heavy-sleeping nerds, the laser target alarm clock is a must-have toy.

Emitting a high-pitched scream at the appointed time, it can only be turned off by hitting a bullseye on the clock with a laser beam, by which time the owner is most definitely awake.

Another firm, Satzuma, proudly displayed its own selection of pointless but fun toys, including a clock powered just by the energy produced by running water and a teddy bear that holds your iPod or MP3 player in its paws and plays music through the soles of its feet.

The CeBIT is always a magnet for the latest in robotic technology and this year was no exception, with intelligent humanoids showing off their ability to vacuum clean your bedroom, empty your dishwasher or sketch your portrait.

But stopping the show was a pair of sleek-white, life-sized pole-dancing robots gyrating in time to the music "played" by a ultra-cool megaphone-headed DJ robot.

Available for your next party for a cool 30,000 euros, these very exotic dancers are made from scrap and driven by old car motors.

Also drawing crowds was a prototype "car of the future" that made parking easy by shrinking itself by up to 50 centimetres to squeeze into those tight spaces.

The futuristic cobalt-blue two-seat pod, as yet only a prototype designed by the German Centre for Artificial Intelligence, will also pick you up at the touch of a button, avoiding other traffic by means of motion sensors.

Hailed as a world first, South Korean firm Neo Reflection unveiled its "finger mouse", a tiny device worn on the user's finger which can control a computer or a presentation just by pointing from up to 10 metres away.

Large crowds also formed around Tobii's eye-tracker arcade game, in which gamers pilot a spaceship through an asteroid field using just the motion of their eyes.

But not all the gadgets on display were just for fun. Some were much more down-to-earth -- literally in the case of the sensor for hopeless gardeners designed by Zurich-based firm Koubachi.

Simply by sticking the sensor in the ground next to your beloved flower and programming it according to species, the machine effectively "looks after" the plant, judging the appropriate moisture levels, temperature and sun exposure.

The sensor then sends the gardener an email or a read-out to a smartphone explaining what needs to be done: more water, lower temperature, more fertiliser, more shade.

But such aid for the green-fingered but hapless does not come cheap. The Koubachi sensor currently retails for 109 euros.

"We suggest it should be used mainly for really special plants," said the firm's head of sales, David Kurmann.