I like
"If you're allergic to peanuts, you may want to tell somebody now, because this next test may turn your blood into peanut water for a few minutes. On the bright side, if we can make this happen they're going to have to invent a new kind of Nobel Prize to give us, so hang in there."
and
"CAVE JOHNSON here. FACT: The key to any successful cooperative test is trust. And as our data clearly shows, humans cannot be trusted. The solution: Robots! Then fire the guys who made those robots and build better robots. Then run those robots through a regimen of trust exercises. Creating a foundation of mutual respect, reinforced by the simulated bonds of artificial friendship. Inspiring stuff. And finally, we put that trust to the test. BAM! Robots gave us six extra seconds of cooperation. Good job, robots. Cave Johnson. We're done here."
-that second one was from a commercial