I have been doing birthday parties and larger events for about 7 years. I have a general contract that I use, it just states the Colorado Law about equine events. It also mentions what there deposit will be and that it is non refundable. How much in advance they can cancel to get back a portion of their deposit. We generally get them to plan two dates, one as a rain date especially if the party is in fall or winter. I just made it myself and have never had any problems. I charge between $100 to $150 depending on how far away the party is, per hour. Generally birthday parties wont last longer than an hour unless there are a lot of kids. We do large events that have lasted 4 hours, but that is ususally done thru like a city or business, and I always take the colorado law signs to have out so they can see them. We have in the past been extremely busy during the spring and summer months, but this past year with the economy it has slowed down considerably. good luck!