These spiders are around my house this year outside m. I haven't seen them before. I live in southeastern Wisconsin. They have very strong webs almost like string. Someone said an orb weaver?
They're not orb weavers, but I'm not a spider expert so I can't tell you what they are. The Insect Diagnostic Lab at UW-Madison (http://labs.russell.wisc.edu/insectlab/) can help you with an ID. Email the pictures to firstname.lastname@example.org.