How do I stop cell phone use in the classroom?
Assume that I cannot confiscate them, and that I have already asked in polite ways.
Cell phone jammers are available, and are ethically questionable on a number of levels - but if you're stuck they are known to work. They range from a few meters to a hundred meters.

Example: http://www.jammer-buy.com/cell-phone-jammer/c-24.html

I know an astronomer that has a green laser pointer. The color might not be the best for pointing at limbs during the daytime, but it sure was powerful and compact. I have a color weakness that makes it difficult to find a red colored dot anyway... He says the green is much brighter for the same given power as red, and the average eye is much more sensitive to green if that means anything.
Green laser: http://www.everyonetobuy.com/green-laser.html
Red laser: http://www.everyonetobuy.com/red-laser.html

Depends on the laser. One cool thing i like to do is to point at things during a presentation.

If your laser is strong enough you can cut things, like steel.

You can measure distances.

Laser pointer can burn matches, cigarettes, paper and popp balloons.

If i remember right, then the Apollo missions left mirrors on the moon, which we now use to measure the earth-moon distance.

They also used lasers for the gravitation wave measurement.

You can entertain your cat and therefore yourself with a red laser.

But as i said, it depends on the laser. There are millions of useful things to do with lasers.

But one thing you should never ever do. Point it at a aircraft. Seriously, that can be dangerous, especially at night. I experienced it myself and it was not funny.

More: https://www.kitlaser.com/strongest-most-powerful-blue-beam-laser-for-sale.html .

High Power Blue Laser Pointer 30000mW, UP TO 45% OFF. Buy one get lightsaber and 8 in 1 lens free. The laser pointer can burn matches, light cigarettes, burn paper, pop balloon etc.
More: http://www.everyonetobuy.com/super-strong-30000mw-blue-laser-pointer-shop.html

According to animal behavioral specialists, a typical cat will engage in at least 8 to 10 ‘hunting expeditions’ a day. It goes the same for indoor cats who have no need to hunt. That’s why house cats can go crazy about laser pointer toys.
Play with your fish. Seriously! Fish follow the pointer like cats do. Their life is pretty boring in that tank, and the feeling is mutual watching them do nothing. It's good to play with your pets.

From: http://www.everyonetobuy.com/wholesale-5mw-red-laser-pointer-pen.html .

Gloves also have a blue palm light, allowing for even more possibilities. Extremely bright LED Palm Lights are fitted on each glove to create an explosive flash of color at the push of a button.

see more: http://www.everyonetobuy.com/green-laser-gloves-with-four-laser-modules.html