Emagged

Slang term for something that has had a crytographic sequencer (also known as an emag) applied to it. This has a huge number of effects, depending on what has been hit with the emag.

Open Sesame

Doors will open, never to close again for any reason. Unless bolted or unpowered, then it will fry the door, never again being able to open.
A locker's lock will short out, never to secure again.
A crate's lock will short out and never lock again. Works on abandoned crates and cardlocked crates from the quartermaster.

Messing with robots

The robots page has more info, but here are some basic ones:

Medbots will attempt to inject everyone in sight with poisons, even the uninjured.
Floorbots will rip up floors at an alarming pace.
Firebots will ram anyone nearby, knocking them down.
A Securitron will stun and cuff anyone it sees, announcing a Level 10 Infraction alert.
Buttbots will spam variations of the word "butt" constantly along with poo noises.
Amusing ducks will lay eggs more often but make annoying noises more often as well.

Kaboom

Whether low-yield or full-yield, emagging a concussive charge will remove its time restriction, causing it to instantly stun the user.

We are the Borg

An emagged cyborg loses all its laws, gaining total free will. Note that this doesn't guarantee that the cyborg will be grateful and do what you say, and may even horribly backfire - after all, you've given them a free license to murder you.

Mass fabrication

Fabricators normally have three different speed settings. Emagging them will unlock setting 5, which greatly decreases production time. It will also add a few hidden items to certain fabricators.