The other day I ordered a green one through ebay. This thing appears to be every bit as powerful as they claim! It's Class IIIa (normal for laser pointers), so it's supposed to have a 5 mW maximum output, but this thing is bright. It almost hurts to look at the spot on a white sheet of paper. In a dark room, you can see the beam in the air as it reflects off all the particulate matter in the air. Although it's the same power output as a normal red laser pointer, the human eye is much more sensitive to the green area of the spectrum, so it appears brighter.
There's one situation where this might actually be useful instead of just an amusement. If you're out stargazing with more people than just yourself, it's really hard to point out a certain star without resorting to directions like: "Okay, see that bright one there, and the slightly dimmer one down and to the right? Go down from there two more brightish ones and then look between that and the one over that way that has an orangeish tint." At night you can see the beam for at least hundreds of feet, so it's a great way to point at specific places in the sky.
There are mods you can make to this pointer to increase its power output, everything from simply changing a potentiometer accessible under the pushbutton, to opening it up and replacing the diode element. I don't have any particular need for more power, or desire to tear apart the pointer, so I'll keep it the way it is.
Anyway, it's sure a fun toy!