[fwonkas]

I don't remember if it has to be configured, but I just press Ctrl-Shift-Eject to lock my screen.

[swampthing]

There's no eject button on Macbook Airs

[GrumpySimon]

Hit the power button. It pops up a modal with restart, sleep, shut down and cancel.

[drivebyacct2]

It's like no one read my post. I specifically do not want to sleep.

[zuppy]

the sleeping is only for the monitors, the computer is still running.

[drivebyacct2]

That's... not true.

[zuppy]

cmd + alt + eject is the sleep you're thinking about. ctrl + shift + eject is just for the displays :)