I went out and weeded around my melon and watermelon plants, and within two hours of that, the cantaloupe plant had completely wilted! I did move some of the vines around to get to the grass underneath them, but I was careful not to disturb close to the roots. The flowers still look okay, as do the few melons that have sprouted. It's just the majority of the leaves and the stems that seem kind of limp also compared to what they were. What would cause this?
I'm guessing stormy is right and the roots were just disturbed by the weeding (and/or an insect); and the sun caused the plant to wilt. Sun will do that to plants with disturbed roots. If you disturb them when it's dark, they're much less likely to show it. Shading the plant and/or removing the large leaves (if they're beyond repair) may help it to survive, if it wouldn't otherwise. Potassium (accompanied by extra water) could help, too. Misting/showering your plant should help some, too.
If you have loose soil, I imagine it's easier to disturb the roots. I've heard people talking about how just walking on the ground by watermelons can cause obvious damage to the roots, but I have no such issues in my soil (which is more compact than most consider ideal for watermelons). People generally prefer looser soil for watermelons, at least. I've had no difficulty growing most muskmelons/cantaloupes in our soil as long as they have enough potassium and rockdust.
Anyway, there are other potential causes, but that's my guess with the current information. I'm waiting on your response to my comments. Others might know more than I do about cantaloupe diseases that might be the culprit.
I often find that my cucurbit plants with long vines wilt in hot sun, so that the outside edge of their large, roundish leaves looks like it's turned down. This summer was especially hot and dry for the UK, and my Hokkaido squash and buttercups frequently looked like this. It doesn't seem to have much effect on the plants that I could tell and some have been quite prolific. It may simply be that by weeding around them you've exposed them to more direct sun.