Ok so here is what i did-
1) Get a hose attachment kinda thing from the plumbing section of a home depot or hardware store. It will fit INTO the hole you are about to drill. The one i got cost 79 cents.
2) Get some tubing that will fit the other end of the plastic attachment thingy. Mine cost about 1.50. It will stay in place from friction, and be a clean fit.
3) Drill hole on the back right corner, doesnt have to be back right or anything, but pick a corner, there is a purpose for it!
4) Hot glue all around the plastic hose attachment thingy, and twist it into the hole - make sure you drill right size so its a good fit. The hot glue will create a seal inside, leaving just the hole to the tube. Reinforce it if you want on the bottom side
5) Tilt the cage and put some stuff under it just enough to direct any dripping water to that corner you went with. I also used some silicone around the bottom inside the cage to seal off all the insides, as it was dripping a few places. If you decide to do this, give at least 24 hours to cure as there will be vapors from the curing process that can harm your chameleon.
6) You can see in the third photo that the cage is up on a bookshelf, only downside to this meathod is that it has to hang over a tad becuase of the plastic hose attachment thingy. I suppose i coulda drilled a hole in the middle of my bookshelf and set it on there, but I didnt want to ruin my shelf, so iI didnt! Just have it catch in a bucket, change daily!