This is a simple script to download the latest 64 Bit Flash player from Adobe Labs and install it locally in ~/.mozilla/plugins.
To run this script, you can execute
wget -O- https://github.com/mss/getflashplugin64/raw/11/getflashplugin64.sh | /bin/bash
If you want to use the older version 10, you can run
wget -O- https://github.com/mss/getflashplugin64/raw/10/getflashplugin64.sh | /bin/bash
Since this is a preview release of Flash, I recommend to use it together with Flashblock.