For the people that want to test Flash 10.1 on Ubuntu 64-bits you’ll notice that there is no 64-bits version. There is a simple workaround.
Install first the flashplayer installer through apt-get (This will actually install flash 32-bits with a wrapper so its works on a 64-bits browser
sudo apt-get install flashplugin-installer
Then download the 10.1 version here and put the libflashplayer.so file in /usr/lib/flashplugin-installer
This will override the current 10.0 version.