Looks like an annual Coreopsis to me. Except that your plant is taller it looks like the Coreopsis 'Bright Lights' from the dollar store growing with my butternut squash right now.

That odd arrangement of the disk flowers doesn't look like any of the Coreopsis species that I've seen. You may need to provide good photos of the back side of a flower and definitely one of the leaves, if somebody doesn't recognize that distinctive head.

Yes, I'd like to see the leaves. It does remind me of Coreopsis lanceolata L.

You've probably already checked this site, but if not, any of these?--

http://uswildflowers.com/wfquery.php?State=TX&Color=Yellow

isn't that cosmos sulphureus?

Possibly Cosmos sulphureus?

I agree on the annual Cosmos sulphureus.

Yup, I think the last two posters nailed it! Now I want one. :)

Thanks all!

One might rather choose to grow its near-relative Cosmos caudatus instead though, because it apparently has healthy, edible leaves that taste like mangoes!!!

Cosmos caudatus has pale pink flowers – but it is mostly grown for its leaves. The young shoots taste refreshing. A friend likened its taste to that of a mango, and he’s right.
I’d gladly eat a whole bunch of cosmos caudatus – it is that tasty, and more so since it is said to improve blood circulation, lower uric acid, reduce body ‘heat’ and is a good source of fibre.