Here are plans for a playhouse with a shingled roof that is built to withstand wind and weather.  
 
Browse over 21 free playhouse plans on FreeWW.com:
 http://www.freeww.com/playhouses.html

Build a backyard fort that promotes fun and exercise. This fort has a hatch, peephole and a flag that kids can design themselves.

Here is a project for a playhouse that looks like a log cabin. Kids will love having a log cabin playhouse where they can have fun climbing on the outside and playing on the inside.