This is an interesting idea that every office needs and could keep
someone occupied for the cold winter months.

http://www.dailymail.co.uk/sciencetech/article-2535224/Thats-got-hurt-Student-designs-85-machine-gun-fires-14-RUBBER-BANDS-second.html?vsmaid=139&vcid=27738

Now if we could just get someone to do it in Sketchup.