Not to be confused with the multi-monitor tool, ZBar lets you use your webcam as a scanner. We have more than a few QR Code generators here on the site, but we don't have any readers even though most laptops now have cameras built into them. So I went digging and found Zbar.
Looks portable and seems to work fine but I couldn't figure out how to get an output other than in a terminal window. I spent some time trying to make a go of this because it's cross-platform, open source, seems to support a ton of formats (not just QR), and is actively developed.
Steps: Unzip executable, run /bin/zbarcam.exe
http://zbar.sourceforge.net/
https://en.wikipedia.org/wiki/ZBar