I recently built my own second bird gym, this time using wood instead of pvc. It's a big hit!

What you need:

A design first... figure out how big you want it to be, take measurements, etc..

You will want at least 1" thick dowel for the vertical rods (supporting- so you can drill 1/2" holes through them)- these are 2.50 at walmart for 3'.

Then you will use 1/2" dowels for the horizontal parts of your gym.- these are about 99 cents at walmart for 3'.

For the base, I used wood shelving I had lying around. You could also use laminate countertops available in sheets at home depot.

Also available at home depot is the bordering for the base- I used plain pine stoppers.. It was available for 59 cents a foot.

You will also need screw eyes- nickle or stainless steel. These are not available at home depot or most hardware stores. I got mine on ebay- 100 for 2.50

Then you can add ladders, swings, and toys wherever you want!

It's really simple to do and you can get the exact gym you want very cheaply (mine cost about $20 to make)

See pictures below (note these pictures are before toys and screw eyes were added):