Couple of garden mysteries
Denver County Colorado
Tomato blossoms don't set fruit if temperatures get too hot. When the daytime temperature reaches 90ºF by 10 a.m., blossoms that opened that
On the others, because the problem came on rapidly in one day, they appear to be grown in containers, our temperatures are hot, and the leaves are curling up, I suspect the plants are suffering from low moisture combined with heat, low humidity, and possibly wind. I do not think there is a disease or pest problem that will spread to other plants.
With temperatures in the 90's, you may have to water more than once a day. You might also check to see that the water to those plants is sinking in - try popping the plant out of the container if you can manage it without destroying the plant and check moisture levels at the roots. Sometimes containers get compacted or when the planting medium contains a lot of peat moss or the like, it can be hard to re-wet after it gets dry.
Here's a fact sheet that might be of help from Texas A&M: http://aggie-horticulture.tamu.edu/vegetable/files/2010/10/E-626-What-Makes-Tomato-Leaves-Twist-or-C...
Thanks so much, this is very helpful. Does any of your information change with the fact that my tomatoes are in a raised bed? I forgot to mention that.
The only thing that might be of concern with a raised bed is the interface between the existing soil upon which you built the raised bed and the imported soil brought in to fill it. The two soils will be different so they need to be blended to unify the transition. You want to avoid two discreet layers because water and roots will have trouble crossing the point where they meet and that will make your plants less able to withstand heat and drought.