This is mine. I wanted to build something that worked for two cages, so I built tables that fit two of the large screen cages:
I basically built a table with raised sides, essentially making a box without the top. Then I decided I wanted to build a sort of "rack" for my cages to sit on, so I took another wooden bar and nailed it to the vertical sides high enough so that the bars and the vertical sides would be flush and even. The rack bars are removable for cleaning and whatnot. Then I took a sheet of PVC liner plastic and nailed it to the bottom, around the drainage hole, and to the sides of the table, creating a sloping angle towards the center. And under everything there is a bucket.
It works super super well, and is extremely waterproof because the bottom is a sheet of plastic. I've tried making the same thing out of just wood and there was never a way to make it absolutely waterproof for a long time with sealers. So far, so good with this!
Edit- I spent a fair bit of money on this, mainly because the PVC was expensive compared to the wood. I think it cost me $40 just for the PVC, so it's not as cheap as the $4 wooden/PVC pipe frames people build for their cages to sit on and just drain into a bucket, but I wanted mine to have the advantage of a margin around the cage (there are 2-3 inches of extra space on every side of the cage) so that if water doesn't come cleanly out the hole in the cage, or if the chams move the misting nozzles and it sprays at the side of the cage and all that drips along the outside, the table can still catch it. And I wanted mine to be solid and, if possible, semi-attractive.