How much work is it to get your boss to a black tie event?

It's a lot of work actually but I've found that it's perfectly manageable if you create a schedule and prepare yourself for the unexpected.

2 weeks before the event, notice that there is a black tie event (BTE) listed on his calendar. Ask if there is anything that you need to do for him before the BTE. He will say no.

1 week before the event, ask if he needs anything brought to the drycleaners before the BTE. He will delay, and tell you that he thinks he's all set but will look into it.

Morning, 3 days before the event, tell him that you're headed to the drycleaners. He will ask you to hold off until the afternoon so he can get his tux together and you can bring it to be pressed.

Mid-day, 3 days before the event, leave your boss a note reminding him to put his tux in the drycleaning basket.

Late afternoon, 3 days before the event, drop off his tux at the cleaners right before they close.

Day of BTE, after two days of him reminding you that he needs the tux picked up today, go to pick up the tux. While you're out, pick him up a selection of shoes to wear with said tux in two different sizes because he's not quite sure what will fit.

20 minutes before BTE, "I was wondering if you were free to pick me up and drop me off at my dinner. The cab company said it would be a 45 minute wait." Sure thing Bossman.