If you are reading this, its because you have installed Ubuntu 10.10 and found out that flash videos don’t play in fullscreen…
This problem has something to do with flash having hardware acceleration enabled
How to fix flash fullscreen on Ubuntu 10.10
Open a terminal and type the following and execute them..
sudo mkdir /etc/adobe sudo su sudo echo \"OverrideGPUValidation = 1\" >> /etc/adobe/mms.cfg
and wa laa!! now the problem is solved ….
(Source : noobrescue)