I sliced them, removed the pit, peeled them, then put them on a plate in the freezer, curved side down. (I made the mistake of doing the first one flat side down, it froze to the plate, and I had to pry it off with a knife, curved side down eliminates that problem.) I let them get hard enough so they wouldn't smoosh all over the inside of the freezer baggie, and when they were hard, I stuck them in, zipped them up, and voila!
Avocado update. For those of you who asked if the avocados turn brown after being frozen, I read that you can mash them first, and add some lemon juice. That should prevent browning, I would think.
Made a Costco trip on Saturday and bought a big bag of avocados!
Honestly I was a little nervous buying that many, but I chopped up like half of them and popped them in the freezer, so they should be good to go.
I am in avocado heaven right now, haha.