All of the teething rings I've seen now specifically say not to freeze them, but we do have this little polar bear teether. It's almost like a beanie baby, but his hands are these cool teethers that have a gel substance in them. This little dude can pretty much go anywhere. Freezer, fridge, I THINK he might be dishwasher safe but I'm not sure. He helps a lot.
He's not a huge fan of bananas, but I tried apples and those helped. Big mess, but he loved it.
These tips have been awesome guys.