In the area of New Orleans where I live (and didn't flood), the only way for people to communicate with the outside world was with land lines and old phones which are powered completely off the line (no wall warts).

Much of the cellular system didn't work. The remaining working systems were nearly impossible to use.

I hate using cell phones for more than a few minutes and always use a land line for long conversations. I also need to keep the land line for our alarm systems.

I was amazed to discover that my collection of 40s - 70s rotary dial phones dial perfectly on the Cox Digital phone system.

As someone else mentioned, how about a Commodore 64, Apple II or Atari 400/800 with a floppy drive?

You can get these machines very cheap on Ebay or free if you look around. They're extremely durable and easy to fix. Best of all, they're easy to understand. You insert a disc, apply power and the desired software runs. No complicated OS gets in the way. Gobs of quality edutainment software available.

I've got a stack of Apple //e's ready for my kids when they're older.