Team Urban Siege's first public plans created completely in-house. This set of plans is a full step-by-step procedure for building a sturdy little desktop trebuchet with a 12" axle height and a total resting height over over 2 feet! Suited well for small projectiles such as those small rubber balls found in grocery vending machines and the like, it utilizes a counterweight of up to 15 ounces and can throw a solid 20 or more feet!
Feel free to check them out, build from them, modify for your needs or whatever. Just do not try selling them or claiming that they are yours, lawyers frown on such practices and you will be found.
Without any further ado, here's the link: Mini-HCW Instructions (.zip file, 775 KB).
You will need to extract the .zip file to access the .pdf file, which can be read using Adobe Reader or any other program that can read a .pdf. Windows should be able to automatically extract the file (right click on it after downloading, click "extract all"). Mac users ought to be able to extract it too, using StuffIt or the like. Feel free to contact us if you have problems reading the file.