after eight years of saving the world with toothpicks, macgyver was recruited by the special ops and trained, and did many missions in secret. this required him to take on a new identity-- jack o'neil (after his friend who helped him save the world with toothpicks), and he was given the job at the sgc. there he met general hammond, who was actually william scully-- dana scully's father, who had faked his death several years earlier to take on the sgc job while severing ties to the previous life he'd led, and also taking on a new name. this was after scully had met mulder, and they spent the rest of ten years chasing the greys, which happen to actually be the asgard; the x-files branch of the government had stollen some of their cloning data from the sg1 branch, and was trying to mass produce them to study them, when really it was the black oil they were after. they were very confused, and as the various parts of the government never talk to eachother, they didn't know what they were doing. when mulder got into area 51 that time, what he saw were the retro-engineered x-302 and subsequent ships, tested by none other then jack o'neill.
now that ben browder is to join the cast, it will continue as such: meanwhile, astronaut john crighton happened to be testing a new type of engine (designed for the retroengineering program, though he didn't know that's who was funding him) and was slingshotted into a much brighter and more colorful part of the universe, where he met many aliens, got married, had a baby, and came back. once back, he reported his findings and was recruited into the sgc, once again taking on a new name (which i don't know yet), and replacing jack o'neill who is getting rather old to be traipsing about the galaxy killing goa'uld.
i need to see that episode i missed with claudia black and see if i can work he in, too.