I'm always a big fan of taking my dad out to do something on his birthday/father's day.
Material items just don't mean as much as spending time with him.
Even still, if he doesn't have that much free time to spend, you could cut the grass for him this weekend so he doesn't have to do it, make a good dinner for him, and do some other work around the house so he has more time to relax.
But you COULD...
-Get him a subscription to SI (since he likes basketball, I guess he's kind of a sports fan)
-If it weren't summer, a nice blanket to use when he's laying on the couch relaxing or something similar would be cool
-A couple good books and a movie
-A decent watch if he doesn't have one
-A pocket knife