The "any" key, of course.

Usually space

I move the mouse.

Space

I pick up the mouse, hold it to my mouth and say, "Computer...?”

ESC

Space key. That way it won't accidentally enter an actual letter or command that could be passed to the current active application.

That's not really much of a problem anymore these days (serious issue in WinXP era), but it's still the safe key, so I use it.

Edit: I totally botched this. I meant Shift key. Derp.

I like ctrl as well.

Less alarming and obtrusive. To the computer? For me?

I prefer left Ctrl, but will press the right ctrl if I'm feeling wild that day.

This is a great question.

Shift because it can't trigger an action on its own.

A nice open palm slap on the middle of the keyboard does the trick for me

Spacebar

Arrow keys

Mouse wiggles

Space, because I enjoy chaos.

qwerdsffyjiluiop;hjmdb

sfg [waggle mouse] qqwthr

ctrl is the only correct choice obviously. it's the only key that does nothing by itself and it's positioned at a corner so it's hard to mistype

Space - The Final Frontier

These are the voyages...

I shake the mouse then start entering my login before the screen turns on, works 50% of the time.

Shift.

They're big enough I don't have to aim. They're located on both edges (at least on TKL). They do nothing on their own.

Any single modifier key by itself, in case it’s just the screen that’s asleep and I’m inadvertently typing into a text field.

Up arrow

I always turn off my computer when I'm done. I like to get a fresh boot

My 2 year old, when prompted to hit any key, hit the power button instead.

Anyway, the answer is a swift kick of my desk to move my mouse cause that seems to wake it up.

Left Ctrl

I always shutdown even for a short break.

I shake the mouse

Up arrow

Mouse click.

I just smack the keyboard or press a bunch of keys at once.

I spam escape but I usally disable sleep on all my machines and use hibernation instead. Too many issues with sleep. Randomly wakes up, USB devices aren't recognized, a monitor stays black...

Fingerprint scanner power button thing

I have to press the power button because the dumbass enters deep sleep.

Wait... You guys actually only push one button?

I slide my entire hand across the keyboard like I'm waving to the computer haha

Been using spacebar but what I would like to do is set up a midi drum pad as an input device so I can wake my computer up by smacking it with a stick.

Lawful Neutral, ctrl.

Backspace, because my cat likes to step on my keyboard and then characters are often left in the password field that need cleared.

I stomp on my usb foot pedal