I hate over protective parents

Here are there reasons:
Dad:
(most important to convince)
He hates the whole idea and wants me to have nothing to do with this
Mom:
Does't like the idea of it "exploding" hairspray as propellent. Although she was impressed by my mini.
This sucks because i always get totaly screwed like this.
4 weeks to convince them to let me have a blowgun, only to find out that they are illegal in CA. (but mom we live in the #&%* mountians. No one will know, lots of people have 'em)
I finaly get a slingshot and the band breaks on like to 3rd shot and mom throws it away

So if any of you can tell me how you won your parents over that would be awsome! I really want to join in the fun.
(seriously our property is f***ing perfect!)