We're making one too

I had one when I was a kid that my Grandpa made. He just took wood, um, not 2x4s but smaller, and drilled a hole through them in the top of each one. Then he threaded a rope through them all, tied it to form a circle and there you had it! It closed up into a bundle of wood after you were done playing. We just threw a blanket over it and held it with clothespins.
Not very fancy :LOL You're probably talking about making a "real" looking one

I'm really looking forward to this one though. Once it stops raining here

: the kids can have some fun in the backyard with it. They don't know about it (shhhh!).