If you're purchasing Assassin's Creed 3 today or perhaps already have at some midnight launch last night, you should be aware a pretty important patch is available for it now, addressing a long list of bugs and crashes. As such, if you don't have your console hooked up to the Internet, get on that now.
Aside from some weird specific "stuck" fixes, there's also a load of mission fixes, crash fixes, and more -- hit the source if you want the full list. Hopefully the breadth of the update means there aren't a heap of other bugs waiting to be found.
PC players, meanwhile, should at least have these fixes and maybe more already incorporated when the game launches for them a few weeks from now.