I need ideas for new organs

[Agent]

There's that one sharks have. That would be a good one. Maybe one that makes you smell nice. Maybe one that lets you eat rocks.

[Samurai]

Snakes' 'heat pits', electric eels' bio-batteries, butterflies' directional pheromone sensors -- I can certainly think of a few. Or straying from reality slightly, the krogan redundant nervous system might be handy.

If you mean original ideas, it's a little trickier, as nature already has a lot covered, but an inflatable hydrogen bladder filled from metabolised water to enable lighter than air flight, perhaps?

[Inferno]

These are in order from least to most important:

Skin things that let you turn invisible like a cuttlefish.

An organ that takes urine and turns it solid and moves it into your rectum so that you never have to pee, like birds.

Better cells that don't turn cancerous, like plants.

[dexeron]

If the organs can be artificial: solar cell skin cells. Maybe they're not perfectly efficient, but they can supplement energy production and let someone go for far longer without eating. Maybe a military upgrade for special forces in the field. (It obviously wouldn't be able to replace the need to water intake, though.)

[Nick]

I want to a radio waves sense