Excalibur has a fairly decent (and expensive--to me, anyway!) arcade on the lowest level.
The Pirate show at TI changed to the siren show several years ago. More adult oriented, but still suitable for children.
If you're staying on the strip and can get tickets for an early show, Lance Burton is a good option for families with children. I don't think the later shows are racier--just thinking in terms of children and bed times!
If you're at the Rio--don't make a special trip--Fantasy in the Sky is nice to watch. It's only about 10 or 15 minutes, so don't make a special trip. And you have to walk through the casino to reach it, which is a pain with children.
If you'll be there on weekedays and have a car, check out the Ethel M chocolates factory tour.
There's a Wet N Wild just off the strip--in the vicinity of The Sahara, if I remember correctly. Never been there--just passed it.
As the PP noted, the pool will be the primary entertainment for children.
Plan on a lot of walking on the Strip--and shopping!
Edited to add:
I haven't been to Las Vegas for two years, so call venues noted to verify information before going there directly. The resort management has been changing during the past few years and resorts are updated/changed constantly.