I didn't totally believe in the "twin" things before they came, and figured even if they were real, ours wouldn't do them since they're fraternal and different genders - I was wrong. It's so funny getting to know them - in so many ways, they're such completely different little people, but sometimes they act like they're on some different wavelength that we can't understand.
The day that Steven was first supposed to come home from the hospital, we were busy setting up the nursery and changing table, and organizing clothes and blankets, when we got a call from their doctor. She said he'd need to stay another 5 days at least, because early that morning, both their alarms had gone off, indicating that they'd had a Brady episode (a common thing in preemies, when they forget to breathe and their heart rate drops). The strange thing was, they'd both done it at the exact same second. She swore it couldn't be a monitor malfunction - she'd looked at the readings herself and they were real.
They haven't done anything quite so dramatic since then, but occasionally I'll look from one to the other and see that they're sleeping in exactly the same odd position (once they each had one hand on their cheek and one fist up in the air), or they'll start fussing together - not one after the other, but together. The funniest is when they "talk" - they both make these funny sounds that sometimes sound like laughing, or dolphins, or (usually) goats, and they'll do them back and forth to each other like they're talking. I love it.
As for how they're different so far, Steven tends to be very physical - always moving, always waving his hands around (he tends to knock his pacifier out of his mouth more often than not - I think he's trying to help keep it in, but doesn't have the coordination yet). When he gets hungry, watch out - he'll try to eat anything around him, including noses and fingers. He acts very angry when he's hungry, with little growling noises.
Eleanor is usually much calmer - if we give her her pacifier and put her hand on it, she'll usually keep her hand still enough to keep the pacifier in for quite a while. She has quite a bit more hair - after a bath (like today), we think she looks a bit like a baby monkey - you know when you see pictures of baby monkeys with their mothers, looking like they just woke up, with their fine baby hair going in all directions? She looks kind of like that after we dry her off.
It's wonderful watching them grow and change every day, and learning more about their individual personalities. I can't wait to see what's in store.