So I recently discovered you can put save files on USB and shit like that. Does this mean you can d/l a whole game and play it via USB?
If you mean download a game off the PC - I imagine it would work if you can find an Xbox compatible downlaod. If you mean download off Xbox live, don't you need to log in to play them? So I'd say yes but it may only work if you were signed in. Not actually tried it myself though in either case - just try it and find out I guess
Nah it won't work. The Xbox will require that you have a legal copy of the game for authentication. Some people mod their consoles so they save whole games onto the HDD.
If you jailbreak it, you can. But that will remove the warranty, and Microsoft can just break your console if you are connected to the net.