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[Reply #15 on:]

Set the pin as an input AND turn off the pullup resistor by setting the output to 0.

That's good!
Thank you very much.

While that is correct what ever you are doing I don't think you need to do this at all. If you are connecting the pin to the input of another chip you do not want it floating as it is called.

He never said what he's trying to do. Maybe it's something like charlieplexing where you want the Arduino completely isolated from the piece of wire connected to the pin.

[Reply #16 on:]

(or let my finger decide)

The Fickle Finger of Fate?  

[Reply #17 on:]

To me... *floating* means... I will allow the mysterious spirits of the Ether and Paranormal to decide the fate (state) of the pin in question.  (or let my finger decide)

Not if you are using wired OR. 

[Reply #18 on:]

(or let my finger decide)

The Fickle Finger of Fate?  

I was messing with an arithmetic circuit (16x16 multiplier - Logic Devices LMU18) that uses a clock and I wanted to use it as a straight combinatorial circuit.  So once everything was wired up it was all working but nothing to trigger the rising edge that causes the multiplication.  What to do?  I soldered a wire to that pin and touching it triggered the multiplication.  There is your fickle finger of clock fate.  Not a smart idea, right?  Fortunately I didn't fry it.   I wired a 555 to produce a 1Khz signal to that pin and now it produces a 16x16 multiplication 1000 times a second, running at about 1/28,000th of its worst-case rated speed.  Whoot.