What new invention would you create with an already existing technology?

[SandraJPulido]

What new invention would you create with an already existing technology?

For example, some new technologies have been already invented such as sunglasses with a build-in mp3 player. What other new invention can be created like this?

[MaryTMartin]

If I knew the answer to this question I certainly would not tell you....I would create it.

[KellyCPerry]

An active power factor correction system using a bank of switched capacitors and inductors. The switches would be semiconductors (MOSFETs or IGBTs) for maximum efficiency.