A few times when I was younger, my dad would catch a bunch of male tree frogs, put them in a jar, and sneak them into my room as I slept. Their sudden, and very loud, calling would startle me and throw me into a bit of a frenzy trying to find where he hid them. (You can be sure when I have kids I'll be doing the same thing.)
For my outdoor adventures I bring a flashlight, but only for when I think I've found a frog. The point of the exercise, for me, is to see how well I can find a courting tree frog by sound alone.
This can be tricky, especially the way they can throw their voice, or when there's a group of them together. You can think you're right on top of a frog, when it's really five feet away.
Tonight I also brought out my camera, to see if I could catch any frogs in action...
I find it interesting that the frogs get so caught up in their courtship calls, that they lose a bit of awareness. Yes they typically stop calling as you approach, but within minutes they tend to get right back at it, usually not even budging as you approach with a flashlight (or a hand).
Some sit right out in the open, while others like to hide in the grass and leaves by the water's edge. Most of the frogs I heard tonight were in a stand of cattails out in the water, where I could not see or reach them. I managed to get a video of one calling - enjoy!