When we enter the testing area, GLaDOS informs us that she has to go attend to the turbines; before she leaves, she sarcastically gives a radically sped up "explanation" of the test we face in the room. Does she say anything of note in this version? I wouldn't know how to go about manipulating the audio to find out...
It appears to be a quote from the first paragraph of Moby Dick (thanks to Billare for figuring that out):
[…], and methodically knocking people's hats off — then, I account it high time to get to sea as soon as I can.
The full passage in Moby Dick:
By slowing it down, and working off of danielkza's suggestions, I've think it's this:
And methodically knocking people's hats off. Then I found it high time to get to the sea, as soon as I can.
Here's a slowed down version if you want to hear it for yourself: slowed.ogg
Or on YouTube:
You can slow this down in game, one of the recent changes by Valve is that now when you use
sv_cheats 1; host_timescale 0.5 it also slows down the sound and not only the game. Playing with that
0.5 value should allow you to hear what she is saying. Just don't forget to put it back to default or you won't get any achievements, thus use
host_timescale 1; sv_cheats 0 afterwards.