my step-brother/step-sister would come over on christmas eve, and have a dinner. usually a honey baked ham, and then we'd watch them open presents which was really awkward when you're a kid. they were decently older than my brother and i, but still young enough that they didn't bring us presents. they'd leave and then we'd watch christmas movies or we'd play games or something.
when my parents were still doing the illusion of santa, they'd set presents out after we fell asleep on christmas eve. as we got older my brother was bad about trying to open presents early and tape them back up. after that point they would keep them locked up in their room. we'd be up before them and we'd have to bang on their door to get up and set the presents out.
*Edi* we'd get to open a present on xmas eve sometimes, but it was always a joke. socks, underwear, etc