Escalator to the moon
What the world really needs is an escalator to the moon. This really wouldn't be that hard to build either. All you'd have to do is tie a rope around the moon with a weight on the end that trails through the Earth's upper atmosphere. Then you'd have to build an escalator to the end of the rope's height.
To get to the moon you'd have to ride the escalator, grab the rope as it flew past and shimmy to the moon. Easy.
The Wonderful Floating city
Contributed by Dr J
Everyone has seen ID4 and those big-ass alien ships that are the size of a city, well this is the same sort of thing. Basically it is a humungus city that rests an an even bigger 'bladder' of steel that is filled with helium.
The Bladder
The bladder consists of numerous cells, so in the event of a compromised hull, the whole thing wont take off like a burst balloon. The steel is thick enough to withstand reasonable damage (see Defense/Offense) and also features 'stealth' technology to hide its girth on radar.
The Powerplant
Big-ass engines are used to haul this city around. There are many engines seen and unseen to give the city a surprising top (attack/ramming) speed. Power is gleaned via a huge array of solar panels on the bladder and incorporated into the buildings. The city can reach a speed to take advantage of continual sunlight and can ascend to rise above niggly clouds. Extra energy can be stored in batteries located inside the bladder and which are used to alter the city's center of gravity by being shifted around on a vast network of rails in the depths of the bladder. This moveable center of gravity provides greater manouverability.
Food and drink
The city itself is fully contained with hydroponic farms and animals for eating etc. The city also boasts a fully operation de-salinization plant for when water levels are low, the city descends to a nearby ocean and sucks up what it needs. Rainfall can also be captured on an impressive gutter system on the top of the bladder.
Defense/Offense
The city has an impressive automated defense system of big-ass guns and also has a formidable airforce. This is for floating city wars and for wars against ground cities aswell, where it can slowly descend on the offending city and crush it if need be without sustaining much damage.
Moveable Earth
Wouldn't it be great if the Earth had big-ass engines on it so it could move around? This way, the planet could be moved out of harms way when comets are on course etc...
How it can be done
Several rocket engines would be placed in strategic (and political) locations so that only one or two need be fired to move in the desired location and then thier 'opposites' fired to stop. Simple. The engines would powered from a mix of Solar energy and nuclear weapons stockpile. Of course suitable engines would also have to be out on the moon so it can be put back when the earth stops, as I would imagine strange things would happen to t if the earth buggered off for a bit. Everyone would be given time to prepare for the temporary move eg. If we are moving away from the Sun, you would need to rug up a bit and vice-versa.
Vehicle Indicator Synchroniser
When sitting at traffic lights, I've noticed that the indicator lights on cars is never in perfect synchronisation with each other. I propose a device that communicates with other cars also waiting at the lights to synchronise the lights. When there are many cars around (eg more than 5), flashy (pun intended) chase sequences could be programmed.
Headphone Jack for Movie Theaters
Simple - Install a headphone jack on each seat in a movie theatre. People who wanna see the movie uninterrupted by other noisy patrons and who enjoy full stereo sound can bring their own headphones and jack in.
Ducted Hot Water
An expansion of the ducted air-conditioning for office buildings, place large vats of near boiled water at the top of the building with pipes delivering it to every desk in the office. Place instant coffee and sugar dispensors at the desktop and you're done.