Bur oaks grow some big acorns at times. Not all of them do, but in general a bur oak produces the biggest acorn I am aware of. They are a white oak as well so they can produce every year. That one you have there appears to be a real nice one. I have seen some the size of a golf ball before. Collect some of those and plant them!
Look at the size of the acorns on this tree! This may be common, but not where I'm from. This tree's acorns are far bigger than any of the other trees around it. Bottle cap for reference. My wife has small hands...
That's a big acorn (and my favorite beer)!
Here is a pic of some of our Burrs from a few weeks ago. Last night my oldest boy commented on how he could see the acorns from a couple of hundred yds away, and that the tree limbs were starting to sag because of them. It's going to be an impressive crop!
If I get home in the daylight tonight I'll take more pics of leafs and acorns. Start an oak ID thread and maybe someone on here can give some positive id's or opinions.
It is extremely likely both of the acorns displayed on this thread are from Bur Oaks; the only other member of the white oak family that resembles a bur Oak (in size, shape and cap covering) is the Overcup Oak. The cup (cupule) on an Overcup Oak usually covers almost the entire acorn (not so with a Bur Oak) and typically an OCO doesn't have the lone hair-like structures growing out the end of the cap (Bur Oaks have the hair-like structures).