I should be charging you milk money for all my random crazy ideas
Calamity 1: A great and terrible space worm has hatched....unfortunately the egg in which it was gestating had been colonised as a planet and now not only have you lost loyal citizens but you have a whacking great space monster smack dab in the middle of your shipping lanes.
Calamity 2: Your only son and heir (insert daughter for the people who argue sexism) has managed be photographed naked playing strip poker in an hotel at a notorious town of vice (this is of course a completely original idea and not at all based on real life events).
Calamity 3: Your long lost uncle has returned claiming that he was the older brother and not his twin and thus rightfully emperor.
Calamity 4: Your wife is 6 months pregnant but you only met and married her 4 months ago
Calamity 5: You learn that your youngest and only living son was the one behind the death's of his two older brothers in order to become the heir.
Calamity 6: The public has learnt that you sent the royal dog off to the firing squad after he pee'd in your slippers, outrage abounds.
actually I have more serious suggestions inline with your post but RL has popped up and I will have to return to edit those suggestions back in.
If you are going to start somewhere I would probably start with Wikipedia -- probably all AAA companies will have a page on there and in many cases I expect they will have a listing or history of their games developed for example Blizzard Entertainment . You should keep in mind though, quite a few games companies have been traded around, had name changes and their products at times re-branded. You might also consider that games not only extend in the commonly perceived realms of computer and console but also into handheld domains and even the gambling industry. The type of information you are seeking is not small in scope and not easily obtainable in a lot of circumstances. You might even give consideration to actually creating a website devoted to creating such a timeline of gaming history and seeking people to contribute by filling in the blanks as one possible method in seeking data.