Yeah I had a crash last night too.
Was playing DriveClub but bounced to the menus to check on trophies before putting the console into standby like I usually do - and I noticed that the usual PS4 menu music wasn't playing - it was still playing DriveClub menu music. Weird. Jumped back into the game and back to the menu - yep - still playing the DriveClub music.
I probably should have specifically closed the DriveClub program, but as a creature of habit I ended up putting the PS4 into standby, but rather than going to sleep like usual, I got three beeps , flashing white lights on the console and a screen with nothing but a circular progress/loading bar, perpetually spinning.
I had to do the manual shutdown (holding power for seven seconds or so) and when I booted the PS4 back up it had to do a disk check.
Not having online is one thing, but crashes make me nervous, and will hopefully help me avoid the game for a few days - something I've tried and failed miserably to do several times already.