growing: a mystery

Volunteers. I guess that's what you call plants that sprout up where you least expect them. Like my little grape hyacinths. Something strange is growing in the garden. I at first assumed it was a weed, but let it grow just to see. Now? It is vining and flowering and doing all sorts of interesting things. I don't know what it exactly is, but my mother and I determined through careful and scientific observation (guessing and Googling) that I have some sort of melon plant in my garden.

Man, I'm hoping its a watermelon, but I think it most likely is a cantaloupe. Or it could be some weird variety brought to my yard by some well-traveled bird. Guess we'll just have to wait and see.