I can't really speak for Moms on my Mother's Day gift suggestions, but on this holiday, I can speak for myself.  Here's some ideas, and I'm sure your Dad, or your kid's dad will like...

1.  Tools! Whenever my wife asks me what I want for a gift idea, I always say tools.  You can never have to many tools and it is a man's goal in life to acquire as many tools as he can before he dies.  You can help him with this.  Look for subtle hints being dropped around, like maybe a sears catalog that keeps showing up with a wrinkled page in it, or choosing a tool set for the picture here.

2.  Not having to do anything we don't want to do. One of my favorite lines is from "That 70's Show" where Red tells Eric when he doesn't want to do something, "Life is full of doing things you don't want to, but you do them anyway."  How true.  One day, just let Dad do whatever he wants to do and don't drag him anywhere he doesn't want to go.

3.  Buy him stuff for his hobbies. Let's hope he has one.  Fishing stuff is always good.  You can usually get some nice lures that don't break the bank, and a good fisherman never has enough lures!

4.  Homemade crafts from the kids. Yeah, even though we are manly men, we still have a soft spot for things made from macaroni or crayon.  Unless you're a grown child, then you're just being cheap.

5.  Bundle of meat & beer. It doesn't get any better than an assortment of meet and beer to go with it.  Hell, we've got plans now for the rest of the day!