Carter's artificially intelligent Smart House could cook up a nifty meal or save the day, as it did when it realized there was a clone of Carter threatening Allison's kids in last week's episode, “Double Take.” She also had Fargo's voice and a sweet romance going with Deputy Andy.

When Taggart's attempts to help Lo-Jack the dog heal with his Nanoids, the tiny machines connect to Fargo's Mental Mouse, which links the cerebral cortex to a computer, and they begin taking carbon form to reproduce. Most specifically they take the form of Nathan Stark, after connecting with his subconscious, making hundreds of copies of him.

This sweet little device got slipped into Fargo's pocket, and of course, he couldn't help but turn it on. Then he was trapped at the center of the M.A.C.A.A. as it began growing, displacing everything in its path. In order to stop it, Jack and Lupo had to actually kill Fargo, at least temporarily.

When Zoe has issues at the thought of having to leave her father and Eureka to move in with her mother in L.A., she begins using a personal therapy device called the A.T.S. However, when she and Jack have a fight, she throws the device at Jack and then people start literally disappearing and no one but Jack can remember them. It turns out the A.T.S. is actually a virtual reality device that Jack's been stuck in.

You've got to love a device that can cause the Big Bang all over again. Unfortunately, no sooner is the device activated for an experiment than Henry and Stark start acting like kids, along with Allison and any other scientist who might be able to shut the thing off. Luckily, Zane Donovan, a brilliant punk new to town helps save stop the Big Bang. However, fixing the dumbed down scientists is an entirely different problem all together.

An anti-missile test goes awry when a drone that's supposed to be shot down, Martha, turns out to be a learning computer that learns a little too fast. Martha definitely has a mind of her own with plans to free her fellow drones, and she can turn invisible. Martha popped up here and there through the rest of the series.

Eureka got it's own superhero in this one, complete with rocket boosters for flying and a superhero costume. Captain Eureka tries to save the day, only to end up trapped in a wall when his unstable phasing device fails him. However, the device also ends up being the only thing that will save a trapped Zoe before she suffocates.

When Sheriff Carter is fired by General Mansfield, he's replaced by Sheriff Andy, a robot. Needless to say, Sheriff Andy eventually became Deputy Andy (and was play by Ty Olsson before being played by Kavan Smith), a beloved member of Eureka and S.A.R.A.H.'s true love.

Henry's unmanned exploration ship contains a look alike for Kim, who died two years earlier. The Kim-puter is actually an organic computer created by the original computer's self-preservation programming, which was developed by Kim and Henry.

Talk about a game changer. The series literally reset itself with this time traveling episode which sent the gang back to 1947, where they met Dr. Trevor Grant. The autistic Kevin somehow set the mystery machine, called the Bridge Device, to work with the help of cell phones and solar flares. When the team returns to the present everything has changed causing anguish and joy. Kevin is no longer autistic, Fargo's the head of G.D., Henry's married to Grace and Jack's still with Tess.

Zane created special contacts called PALs that allow the wearer to detect potential danger. When Jo and Carter's PALs detect a cataclysmic explosion, they try to track down the cause. But, of course, nothing can go as planned. Fargo borrowed a pair for himself so he could impress Holly and overloaded the system.

When a supercharged light beam begins slicing through a Presidential convoy, things get dicey for the gang at Eureka. Thanks to an ionic charge, the rods can create black holes. Luckily, a rod and a rocket can also implode the hole.

It's Christmas and everyone's running around with last minute plans, at least until Kevin and Zoe decide to let Jenna open just one of her presents early. Before you know it, Jenna's Holotown toy has turned the entire town animated.

It was a creative way to bring Holly back to life. In essence, the Eureka gang created a clone of the original Holly and downloaded her mind, which has been rescued from the Matrix. However, Holly was just getting used to her new digs when an email sent her into body swipping mode as she began to make doubles of everyone in the town, including Sheriff Carter, with plans to hook them back up to the Matrix.

Locked in a virtual reality, Allison and the Astreus crew find that things have changed when after their Astreus mission, SARAH's running GD and there are Matrix-like Andys keeping the town under control. However, when they discover the truth it takes Carter going virtual to rescue them.

When a giant fireball ruins Carter and Allison's day out with the kids, the culprit turns out to be Parrish's new firefly, a collection of nanoparticles that are supposed to put out fires. While the firefly sometimes puts out fires and sometimes creates them and seems attracted to energy sources. However, when the firefly splits in two, things really get hot, especially when it all has something to do with the zeta brainwaves of the people who were jacked into the Matrix program.

Finally! After seeing Sheriff Carter looking up at floating items for years in the ads, Eureka had it's own floating experience. It starts off with a bank robbery, but actually turns into a missing bank that has floated away. While other things begin to float up, Carter discovers there's some items in the banks safety deposit boxes, antimatter and an old anti-gravitational device that was thought defunct. Not so much!

Zane and Fargo accidentally take off in an antiquated space shuttle that has a faster-than-light-drive, and end up in trapped in space. While they almost end up annihilated by missiles, it takes a cloud exciter, an electric pulse and the gang at Eureka to save them. The FTL drive later drove the storyline for the Astreus mission and the arrive of Holly.

Tiny, the interstellar explorer robot, was supposed to be on its way to NASA when it developed a connection with an emotionally intelligent robot called Emo. Of course, other issues ensue and Tiny goes on a rampage. Tiny was blown to bits in episode 417, “Clash of the Titans.”