I found it in my basement... I shall bring it to the minor rec on Thursday. Be warned... once I show it to ya I shall ask whether it is legal. I don't have any legal bolts yet though. I shall make some if it is legal.

(it is about the size of a crossbow)

Sweet! That sounds really cool. You should definitely bring it.

There are, sadly, no official rules on what legalizes siege weapons in Dagorhir. However, the current crossbow rules are:
4.5.3.3. Crossbows must have a maximum draw weight of 35 pounds or less at 12 inches power stroke. Power stroke is defined as the distance the string moves from its rest position to its cocked position.

Also, any bolts you make must not weight more than 1.5 lbs. If you're adamant about making some mini ballista bolts just let me know. XD

haha thats to cool you should dig in your basement more!!!

At school today I realized that it is not actually a ballista... it is lacking wheels =( therefore my next project is to put wheels on it =D