Yes, October 15th is first runner-up to September 15th in the realm of terrible tax filing deadlines, but it is not short on pain for CPAs who specialize in the dark arts of taxes.
If you or your clients are still rounding up K-1s and whatnot, Joe Kristan has a nice round-up of steps to take to (try) beating the deadline. If you're fortunate enough to have everything wrapped up, great! You get to enjoy this mashup of happy people dancing in movies without any feelings of dread:
Happy October 15th.