This vine is growing over everything in the forest behind my land in the Texas Hill Country. I wish I had pictures of it when it flowered but just noticed it. The pods look very much like a cucumber but have a milky-white liquid coming from the stem end when cut and the pods are hard, woody and full of seeds. It seems to be pretty invasive.
Thanks to"nitejasime" I do belive this is a milkweed, specifically Honey Vine. Try this link to see it better. This is another picture of the pods. I will try to take a picture of it when the pods open.
I've this vine on my woodland backyard. Last year I've seen one seedpod. But so far this year I havn't yet. The leaves on mine aren't variegated. And the seedpod is smaller about the side of an okra, pictures above appear as big as a small cucumber? So far I haven't seen much straying seedlings, but when I do. Weed-b-gone will be needed. The seedpods are interesting though.