It would more helpful if we could see an image before you cut it open.

It was a tan ball.

Perhaps an oak gall, caused by insects and not a fruit.

It is a fruit. Not a gall.

Do you have a picture of the plant it came from? I also think it is a gall and the hole in the centre supports that theory. Scroll down the link until you get to Andricus californicus - California Oak Gall Wasp and see what you think.

Here is a link that might be useful: Oak gall

I thought from the very beginning that it was an oak gall.

I am more inclined to think it is a drying Cornus kousa fruit or that of the Arbutus menziesii. In the Carolinas where this was found the Kousa is fruiting heavily.

Doesn't look like either, does look like a gall.

Are you seeing Madrona trees elsewhere in the Carolinas? Often hard to establish and maintain as a deliberately planted garden specimen even here in its native area.

I think it is a gall too.
Remy

Cornus or arbutus fruit are very fleshy and would tend to rot (if not consumed by wildlife) long before they would dry and turn brown.

Looks very much like the oak galls I've seen.

Cornus kousa fruit have polygonal segments (I think maybe pentagonal) all over the outside, each with a raised bump in the middle. Right now they are still bright red on the outside and very fleshy. Mine have not ever turned tan. As Flora said, the little hole in the center is one of the indicators that this is a gall.

zorba, so far...that's 7 to 1, lol. Have we convinced you, yet? Check out google images on the Oak apple gall. You'll find some that look exactly like yours.

I don't know anything about oak galls, madrona, or C. kousa, except what I have read since opening this thread. What I do know, though, is that fruit should have seeds, so I've looked up the seeds of both Arbutus menziesii and C. kousa. Both should be easily seen when opening the "fruit", and they aren't in the OP's picture.
C. kousa: http://www.google.com/imgres?q=Cornus+kousa+seeds&hl=en&sa=X&rls=com.microsoft:en-us:IE-Address&rlz=1I7SNNT_enUS496US496&biw=1205&bih=598&tbm=isch&prmd=imvns&tbnid=BGS2SQAaIEeTcM:&imgrefurl=http://www.thegardenhelper.com/ubb/ultimatebb.php/topic/68/4419.html&imgurl=http://i31.photobucket.com/albums/c354/Gail21676/kousa01.jpg&w=470&h=300&ei=Q18-UNfTN-eOiAKrxYCwAQ&zoom=1&iact=hc&vpx=246&vpy=106&dur=35&hovh=179&hovw=281&tx=155&ty=110&sig=110621673621971630212&page=1&tbnh=121&tbnw=173&start=0amp;ndsp=19&ved=1t:429,r:7,s:0,i:97

Here is a link that might be useful: Madrona fruit w/ seeds

You have gall, lol.

The tiny cavity in the middle is another clue.