One of my Delicata squash plants was developing round fruits and I couldn't figure out why untill I looked at my seed packet pictures today. I somehow planted an Early Silverline melon in that spot with the squashes before or after chipmunks ate the first round of seedlings in that spot last spring. Why is it a good screw up? Those melons didn't grow in the other spots they were planted, but I have plenty of squash.
I can't grow squash in my veggie garden at all, because it is always attacked by root borers. But I left a couple of the volunteer squash plants that come with my compost go in flower beds. One is now huge, totally encircling the flower bed and has a full sized butternut squash ripening up on it...
I don't know if the same trick will work next year or if the root borers will eventually find them...
You should see my meticulously detailed garden plans I pored over and endlessly re-drew early this spring. When it was actually time to plant, REALITY didn't exactly jive with the "perfect plan": number of starts didn't match up, scale was off, volunteers were allowed to grow, etc.
... fast forward to present -- My garden notes from last Monday just indicated that I sowed seeds (I did say which seeds) in this bed and that bed. I'll just have to see what comes up later because at this point, I've no clue what I did.