The rudest t-shirts are the ones that hold nothing back - there might be some derogatory language, a particularly suggestive catchphrase, a potentially offensive graphic or some combination of these things involved.
Finish the Fight: This catchphrase reminds players that this is the final entry in the Halo saga and in order to complete the story, you will need to finish the fight.
Believe: This has become the primary catchphrase for the game, as shown in a series of television spots where Master Chief is held up by a Covenant commander.
Bill Mumy played Will Robinson, famed for the catchphrase 'Danger, Will Robinson', as often spoken by the expedition's robot.
If you have a big group you have to entertainment, the electronic version of Catchphrase is a great large group party game.