Balloons are cheap, easy to find, and fun. But what about using them for a dog toy?
Dogs tend to bite them, then try to eat the pieces after the balloon explodes. Not a good thing. But you can teach them to volley a balloon and not pop it, after which there is a ton of fun.
First thing is to teach your dog to 'target'. This just means that they bump your hand with their nose, without using teeth.
Teach this by holding out your hand, flat to their nose.
After they reach out to it, even if they don't touch it at first, say 'yess' or click, then treat.
This is a good thing to teach them for learning how to turn light switches on and off, or just for manners. Don't treat if they bite!
Once they get the idea of doing it with your hand, start using the cue 'target'. Then you can ask them to target different things; your shoe, the ball, a target stick, or anything else.
Always reward if they do it correctly.
Now comes the fun part. Blow up a smallish party balloon, not too tightly. This will cause some excitement, if they've never seen anything like this before. I suggest training one dog at a time, so the excitement level doesn't get too high.
You also need to have a strong 'leave it' in case they reach the balloon before you do. They won't bite it more than a couple of times, especially if you pretend to be really sad when it pops.
The next step is to target the balloon while you're holding it. Let them get to the point where you hold the tied end, while they bunt it with their nose, getting used to it moving. You can start using the cue 'volley' at this point.
By now, they should be getting good at targeting it while you hold it, so start holding it up in the air while asking for a sit if they look like they want to jump.
Drop it so it goes towards them, then ask them to target.
If they volley it back to you, lots of praise. Repeat this several to many times, and then start to volley it between you. When two dogs have this down, see if they'll volley it to each other, with you in the middle to referee.
By this time, I'm going to bet that the moment the doggos see you getting a balloon ready, they'll get into position. This is a great activity to do indoors on rainy days. Make sure they have good footing while playing.
This game can be played by any sized dog - no need to match them. My ten pound terrier played this with a sixty pound Australian Shepherd x Husky, with the terrier jumping up to three feet off the ground. There are no limits to the fun.
Next step; see if they will do this over a net, just like human volleyball.