Again, you already know the answer.
Father's Day creeps up every single year and it's not fair to dad that you're scrambling at the last minute. Step up your game, you guys:
Teroforma Whisky Lover Set / Sometime's it's the little upgrades that make a huge difference (i.e. whisky stones). Step one: educate yourself on scotch vs. bourbon. Step two: Buy a bottle that's one shelf above what you'd buy yourself. Step three: Figure out which one of these you can stomach so you can have some (wo)man-to-man time with your dad.
Dollar Shave Club / A gift that keeps on giving is always a winner. Your dad will get razors every month, shipped right to his door. Cheap for you, thoughtful and convenient for him. Everyone wins.
This Is Ground - Cord Suite / Chances are, your dad has a lot of electronics. And chances are ever better that his cords and related accessories are a rumpled mess in his briefcase. Help him add some well-crafted minimalism to his day-to-day.
Sports & Games / Your dad is probably into at least one sport - be it baseball, golf or NASCAR. Buy a pair of tickets to whichever one he likes best. Game day won't even be about the game, it'll be about being with your dad in his element. Whatever that may be. And hey, he might even teach you a thing or two.
Robe / Yes - it's summer. No, it doesn't matter. A robe is the one gift every man wants but never asks for. Every single one. I have multiple sources.
When In Doubt / Okay, I know I'm being a broken record here, but your dad is most likely really similar to your mom. He just wants to kick it with you. Go golfing, make a greasy breakfast, get beers, do whatever your dad wants. Make sure you do all the planning, though. It's not your dad's job to orchestrate his own father's day activities.