Attribute Changer
Attribute Changer is a file attribute modifier for Windows. It allows you to modify various attributes of files in the Windows file system. Beyond the standard attributes Windows exposes (read only, hidden, archive, index, and compress) it lets you toggle the system attribute. It also lets you change the created, modified, and accessed date time stamps of a file. It's rare that you'll need to adjust a file's attributes, but it works great. The program uses an unobtrusive nagware model where it asks for donations in its about page.
Personal
I had some old DOS files with corrupt time stamps which was throwing off sorting. When I went to fix them, I was annoyed to discover that Windows doesn't let you change a file's time stamps. So, I went looking for a program which could do it and found this.