How do you decorate for a child's birthday party?

I have two birthdays coming up in game. One is a child aging to a teen the other is her brother aging from Teen to Young Adult. The child will have her party at a bowling alley that has a party room. For her brother I am debating between a party at home then going out to a club with friends or a restaurant party. I won't have to do the decorating for either of those. Since I play with only partial walls the decorations were up in their last house for about a Sim year