4. How to Peel an Avocado Using a Push Pin

Clean the push pin with soap and warm water or dip it into isopropyl alcohol.

• Insert the pin about 1/32" deep (1 mm) at approximately the middle of the avocado and make two incisions - one around the equator and one along the length of the fruit, using the pin as a plough (plow?), never going too deep, but only enough to break the skin of the fruit.
• Lift one of the corners of the broken avocado skin with the push pin and peel slowly away from the avocado. Repeat the process with the rest of the peels.
  

You will be surprised how easy it is to peel an avocado fruit this way and enjoy it at work when you don't have access to a knife or a spoon :)

3. Metal Detectors in Street Sweeping Trucks

While walking down the street during a lunch break I found a penny - sitting on the street side of the curb. This made me think of the possibility of installation and redesign of the existing sweeping systems of the little trucks used for cleaning the streets in most cities - to include a small metal detector and possibly even metal sorting mechanisms to collect such coins (and other metals). While I agree that the "revenue" from such installations will not be big, there is always the opportunity for that rare find which will make the day of a "street sweeper". In addition it could be beneficial if such metals can disposed of properly / recycled, rather than being disposed of in the landfills.

Seems like some other folks think that street sweepers might bring some decent finds: http://metaldetectingforum.com/showthread.php?t=63654

Maybe not that bad of an idea after all ;)

2. Brakes Systems - Vehicle Shape Changing ReDesign

While brake systems in a lot of transportation vehicles have evolved since their first designs, one aspect of the brake systems hasn't changed much - the ability to adjust the shape of the body of the vehicle to create more drag / friction upon engaging the brake.
Such ability would be beneficial especially in emergency brake systems, where the "cost" for engaging the brake could be higher, as it is rarely used.

Example with trains - when an emergency break system is triggered, the only reaction is for the wheels to lock down.A design improvement would be to also change the shape of the body of the train, so it is more resistant to air.

Other similar examples in such re-design would be:

Ships - deploy a steel plate or similar in front of the ship, so the shape of the whole object has more drag in the water, when trying to stop the ship (in an emergency or other). Such plate can be rotated if the ship needs to turn, instead of just stop.

Cars - change the shape of the car (on demand) just enough, so it is not so aerodynamic and stops faster.

Airplanes - deploying parachutes during the landing phase (during emergencies especially) would limit the need for longer runways for the heavier airplanes. This re-design has actually already been implemented with high-end equipment (like military aircraft, the space shuttle and similar, but there is no reason why it couldn't be adopted with commercial aircraft as well.

1. Glass or Stainless Steel Container Food Processors

There are plenty of options for Glass Blenders, but not a single consumer oriented option currently on the market - for a Glass Food Processor.
While it is understandable that designing such device is more difficult, the premium price one would pay to have such quality product should be able to offset the design costs.
There are limited products of such kind available, even among the professional rated food processors.
As all glass containers break eventually - the manufacturer of such product will be able to sell additional accessories (at very high prices...) to the consumers, thus expanding their profit margins derived from a single product through its life cycle.

Design idea: Food processor with Glass or Stainless Steel container.

What does it improve on: No more chemicals (BPA in some cases) leaching in the processed food. No matter how hard a plastic container is - with the years of use, high temperature, acidity of food, etc. - some leaching of chemicals from the plastic into the prepared food will occur. Not so with Glass Container.

How hard is to design it: Easy - all that is needed is to design the Food processor around the suitable glass bowl, and not the oher way around.