|The hybridizers are having fun!|
There are plenty of articles on growing them successfully, so I'd like to share a few tidbits you may not find elsewhere.
1) They may or may not bloom for Christmas. If they've been grown in the southern hemisphere they'll have fulfilled their full dormant period and should be ready to start growing as soon as you pot them. If they've been grown in the northern hemisphere they may need more "rest" before the show begins - so be patient. They'll brighten winter days in January and February just as well.
2) Water thoroughly when you first pot them. Don't water again until you see buds or leaves emerging from the neck of the bulb. That may be weeks if the bulb is still dormant. That's okay. If the bulb isn't ready to grow, don't force it by watering. That may lead to a rotten bulb. It'll grow when it's good and ready.
3) If you're trying to save the bulb to rebloom for next year, feed heavily throughout the spring and summer. It takes a lot of stored energy to produce those enormous blooms. I read once that for every four leaves the plant produces you should expect one flower spike the following season.
4) I'm loathe to mention this as is seems horticulturally perverse, but for those that have suffered tall amaryllis, they can be given a 4-6% alcohol solution (absolutely no more). This will stunt them and keep them more compact. Flowers will be full size, but the stems will be shorter. You'll need to Google that formula. I won't dispense moonshine concoctions for innocent amaryllis.
If I was a parent or grandparent with young children trying to interest them in the natural world an amaryllis race seems a perfectly fun place to start. Gentlemen, ladies, start your plants.