Bloopers, goofs and continuity mistakes have always been part and parcel of moviemaking. When a scene is shot over several days, props can rearrange themselves, or articles of clothing can appear or disappear mysteriously. (Even worse: when jet airplane trails appear in medieval skies or watches are worn in 'The Ten Commandments.') Film buffs have always had fun with such gaffs, so it's no surprise that 'X-Men' fans were on the lookout during 'X-Men: First Class.' The folks at IGN put together what they call "The F'd Up Timeline of 'X-Men: First Class,'" a cool animated video explaining some of the timeline mix-ups between 'First Class' and the many other X-Men films. Watch ahead.