Extract recursively using 7-Zip
If you are using Linux, you can use
find -iname \*.zip -exec unzip {} \;
(after installing unzip)
In Windows, you can use
FOR /F "usebackq" %a in (`DIR /s /b *.zip`) do 7z.exe e %a
Assuming that you have 7z.exe in your PATH. Run that command in folder where you want to (recursively) unzip all zip files.
Use the open source Multi Unpacker tool for Windows. It requires you having installed WinRAR, but other than that it's actually pretty versatile...
