I've had my fair share of history tests over the years (I do have a degree in the subject, after all). And yes, for some of those tests, I didn't study nearly as much as I should've. I certainly did wish I'd had access to a time machine. If nothing else, I'd go and study a bit more and then come back, but going back to the events in question could've also worked. And that's just what you're doing in Bill & Ted's Excellent Board Game, now available from Steve Jackson Games.
Your job is to go through history, collecting various significant people from various historical events. There's a problem, though, as each time you grab someone, the phone booth will break, making your trip through time just that much harder. Get the info and get back in time for the test.