Actually this is something that would be quite hard to do. As you might now, space is pretty close to being what we call a vacuum; this just means that it doesn't have much stuff in it. In contrast, air consists of a few different gases, so in any sample of air there are many atoms and molecules all whizzing about.

If you took a box of air up into space and made a small hole in it, the effect would be similar to taking an inflated balloon (which contains a higher concentration of air than the outside) and pricking it with a pin. You might want to give this a try if it's been a while since you've done it! Because the atoms and molecules that make up air like to be evenly distributed rather than bunched up in one place, they come rushing out of the balloon. The balloon ends up deflated because the plastic that its made of doesn't have any structural rigidity of its own; its shape was maintained by the excess air pressure. Notice also that it flies off in the opposite direction to the hole; it does this to balance out the gasses that have rushed out of the hole side (you might have come across this concept in class as "conservation of momentum").

Releasing air in space would be similar, but a lot more dramatic, since the difference between normal air and a vacuum is a lot bigger than the difference between air inside a balloon and normal air.