Revealing: As we know, the watery image of the event horizon is projected onto a blue backdrop. In "Origin" the third episode of season nine, Ger'ak comes through the Stargate and we can see the image of the event horizon, though faint, around and above the Stargate itself and is not confined to normal area for the event horizon. Blatantly visible if you look for it on the airing of the episode on the Sci-Fi network.

Continuity: When Teal'c attacks the blonde Jaffa, the Jaffa has a staff weapon, but the shot changes when Teal'c hits the Jaffa and the staff has disappeared.

Continuity: In the episode "The Shroud," during the scene where Jack is talking to Daniel aboard the Odyssey, there is only 1 star on each of his shirt collars, indicating that he is a Brigadier General, instead of the proper two stars for a Major General, as he does in every other scene of the episode.

Other: Season 8, Episodes 16 & 17 - "Reckoning" The Replicator ship on which Daniel is being held prisoner is supposedly made entirely of Replicator blocks (a fact established in earlier episodes), yet only the walls of the set are made to look that way. The floor, visible repeatedly throughout the episode, is simply a concrete slab painted the same gray color as the block walls.

Factual error: Before SG-1 switched to P90 PDW's, they carried MP5 submachine guns. They were often shown with a full magazine taped to the bottom of the one in the weapon, so that to reload, all they have to do is remove the magazine, turn it over and insert the full one. Problem is, real special ops troops are specifically taught in training never to do this. It's far too easy to damage the lips on the spare magazine, rendering it useless.

Continuity: In Season 8 - Threads, when Sam is talking to Jack in his backyard (barbecue scene), the back door behind her opens and closes between shots.

Continuity: Season 7: Lost City. When they are about to blow up the ancient device at the ruins, Col O Neill sticks a wad of C4 to the wall in the corner, when the shot changes, the explosives have moved approximately 6 inches to the left.

Continuity: Season 9 Episode 13 "Ripple Effect": When "Desert Camo" SG-1 returns to their dimension through the Stargate, we hear 5 "slurps" indicating someone passing through the gate, however there are only 4 members on the team.

Plot hole: Anytime an SG member starts acting weird or something happens that is "impossible", SGC personnel always act skeptical about it. Considering what they have seen in the course of the show, "that's impossible" should have long ago fallen out of their vocabulary. And while I realize that Sam and Daniel are scientists, they have seen enough examples of incredibly advanced technology that they should be far more open-minded when looking for explanations.