I have been excitedly watching these flower buds grow bigger, but i won't be around to see them bloom. These started out as one or two leaves from other peoples plants. It took a few years, but they are big
enough that they decided to bloom.
The first photo is of the thanksgiving cactus (Schlumbergera truncata). These flower buds did appear a bit before the others. Maybe they will open up first...even though they missed thanksgiving.
The other photos are of a couple of christmas cacti (Schlumbergera russelliana).
I have another one which may be an easter cactus (Schlumbergera gaertneri), but after a mishap, it is just a couple of small leaves and not trying to bloom.
Edit: There's been a lot of name changes to both the genera and species of these plants, and a fair bit of misspelling on the internet. Many plants getting passed around may, in fact, be hybrids. So, without genetic testing, these guesses are as good as i can do.