So I'm here to say Blwyddyn Newydd Dda a Nos Galan Dda i Chi!/Happy ('Good') New Year and Happy ('Good') New Year's Eve to (all of) you!
Nos Galan has recently had a resurgence here.
The Mari Lwyd (which I mentioned at Halloween) visits pubs and homes around Christmas & New Year more often now (though still not as much as it did previous to the 20th century) and the Nos Galan races are run at Mountain Ash to commemorate Welsh folk hero Guto Nyth Brân.
In my family, we have our own tradition - at midnight we open the front door to let the New Year in, and the back door to let the Old Year out.
This is a tradition scattered throughout Britain, which my mother's family has done for generations.
Whatever you're doing tonight, stay safe, have fun, & I'll see you in 2017!