Hi, Simon Pegg fans! If you have Mplayer installed, copying this into your console (gnome-terminal, konsole, xterm, etc.) should let you watch the Paul trailer in Linux!
mplayer -cache 200000 -user-agent 'QuickTime/7.6.2 (qtver=7.6.2;os=Windows NT 5.1Service Pack 3)' http://trailers.apple.com/movies/universal/paul/paul-tlr1_480p.mov
It will queue up to about 20% before playing. Give it a bit of time 
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Once the video is playing, pressing the ‘F’ key will go fullscreen. Alternatively, you should be able to use your favourite Mplayer front-end like SMplayer or GMplayer instead of plain Mplayer to get a pretty interface.