Guilty with the yelling here too, but sometimes, it's the only way to get their attention.  have you tried just sitting in the middle of the floor, turned slightly away fromj them looking at the floor.  Oh, and not making a noise.  It might make them stop what they are doing in order to see what you are upto.  Or you could always throw a tantrum, like I imagine they would on occasion, again on the floor kicking and all!  Any thing that is new and would shock them would work.

Could you engage in some quiet play with them? If they are being just too loud maybe start a quiet game like hide and seek. Read a book with them. Draw some pictures together or do some painting or other art activities. If their mind is occupied and they are trying to concentrate on a specific quiet task they will stop yelling and running amok.

Another idea is to let them outside to run it off. Go out for the afternoon if being cooped up inside is too much. Maybe a trip to the park, museum, botanical gardens or something like that.

Another idea is cooking. This usually calms roudy kids and they are always so proud of their efforts when they have finished.

If you don't want them running around playing superheros maybe you could stop them watching it. My nephew is almost 3 and he isn't allowed to watch anything except ABC kids. I am much the same. My son will never be watching anything violent or cartoons because these programs can cause violent behaviour in young kids.

Maybe it's time to teach them about inside voices. If all else fails, crank some music up really loud and dance with them. Don't worry how you look, they will have a ball!

Have you tried ear plugs or a mp3 player?  Serious, not joking!  I don't know, my three year old who is days away from four has suddenly gotten really loud and vocal.  I have read a book called Raising Boys and learnt that at about  the age four they have a surge of testosterone, so i am putting it down to that.  We can be quite a loud family, but no one would be heard if we weren't

My yoga teacher swears by going into the childs pose when the kids are 'carrying' on - maybe you could try that.  I'm sure you would render them speechless!!

How old are your kids?

My son is 3 1/2 years old now and just starting to have a little bit of volume control. I remember several months ago loosing my voice and and because of it I had to just mouth my words. Lo and behold, my son quited down most of the time in order to figure out what I'm saying. :-) But I needed to get his attention first though. And other than this, it's a constant reminder not to be loud when we're out and about.  Just a couple of weeks ago,he was able to join the family at church instead of going to the church nursery. Again, I had to constantly remind him to whisper but it's finally working. The other thing I do is to do a lot of pep talk before we get anywhere. I tell him that he must be quiet or we will have to stop going there, etc.

I hope you get a lot of good suggestions from others. Good luck.