Since this is my entry into the Make to learn youth contest, here are my answers...
What did you make?
I made an airsoft gun from a pill bottle that an shoot 20 bbs per second. One day I saw a video on youtube and I was like, "Hey, I'm bored. Why not try this out and see if it actually works?" and thus, I made this. You just load the BBs in through the container and you blow through the top hole. The air that goes out the pen takes the BBs out with it. Thank you Kipkay!
How did you make it?
Well, one day I was feeling a little bored and I felt like making something. I no longer use instructables very much because pretty much the only things that are on there are just costumes (hint hint!) so I went onto youtube to find something to build. I found this video by kipkay that claimed this was an "EZ airsoft machine gun", so i said, "Looks easy enough. i'll try it." I just went out into the garage, drilled a hole in the bottom of the bottle and one in the side, both large enough for a BiC pen to fit through, and I hot glued a bic pen into the bottom hole. I think the dimension of the hole was like 5/16", but I'm not sure. Easy enough.
Where did you make it?
Home. Derp. I just wanted something to use as an airsoft gun so i could have an airsoft war with my friends, and this worked.
What did you learn?
The biggest challenge was probably keeping the seal airtight, and also cleaning up the BBs. I'm proud of the fast speed it fires at, despite being made out of trash. I would probably add a mechanism preventing inhalation of the bbs if i had to do it again, which would probably be another pen.