Question about green lightbulbs for viewing in the dark : With Pics for FUN!

Hi all! I've heard that I would be able to look at my plants when they're in their night time cycle if I were to get a green light bulb for light.. My questions is this: Do I need a specific type of bulb or will any green coloured "party" lightbulb do the trick?? I ask because I may or may not have delayed the flowering process (currently day 74 & still new growth) by turning on my light at night (just for a couple mins mind you) to show some friends what I had accomplished.

I'm thinking of just screwing a socket into the board that the light/deflector hangs off of.. Any ideas guys?

I've got a 250W ballast, MH for vegging & HPS for flowering.

And now as promised... PICS!!!

On the left is Master Kush, right is White Widow.