Hasn't happened to me in Forza 5, but I read an interesting tip about the NBA 2K14 crashes (which does happen to me) which you may want to try.
There are apparently some issues with memory leaks and/or cleanup, which can accumulate the longer you use your console (i.e. loading/exiting games and apps). If you actually unplug your console for 15+ seconds and plug it back in, that should clear any residual information in memory including any memory issues that plague your game.
It's not a real fix, but I would rather use this workaround for now than continue to have NBA 2K14 crash on me. Might be worth attempting for you?