The military has been investing in several different kinds of fancy bullets over the last few years, from bullets with smart microgrenades to bullets with fins that can steer to their target. And in order to be able to use the right bullet for the right task, the Army wants a gun that can custom-select ammo at hundreds of rounds per minute.

If your parents ever yelled at you to get out of the house to get some exercise (or if your own conscience bugs you about it) but you didn't want to stop playing Call of Duty or Halo, Hasbro has a compromise: Lazer Tag, which mixes first shooting video game play with the real world. Update at the bottom of this post.

President Obama gave all the kids the presidential seal of approval as he checked out the projects at the White House Science Fair, but when it came to Joey Hudy's Extreme Marshmallow Cannon, he insisted on actually testing the thing out.

The XM25 is a $35,000 weapon that fires tiny little 25 millimeter grenades up to 500 yards. But these aren't just any microgrenades: they're smart microgrenades that can penetrate heavy cover and then explode when they're on the other side.