Hogmanay
Hogmanay is a purely Scottish tradition, also celebrated in some parts of the north of England. It is celebrated on New Year's Eve. It is not a British tradition at all, being purely Scottish. There are massive street parties (100,000+) people in Edinburgh, and local celebrations elsewhere. There is also a great deal of fantastic television specials, from Scottish comedy shows like Chewin' The Fat and Only an Excuse. Large amounts of whisky (it can only be called whisky if it's from Scotland) are consumed, large amounts of food is consumed, lots of pipe bands play, sometimes people even commit karaoke. 

Hogmanay is the best party of the year
Scottish guy: I'm goin' hame fur Hogmanay!
English guy: what's Hogmanay?
Scottish guy: *Hiccup* What did you say about ma maw?

If you aren't celebrating Hogmanay, your life isn't worth living! Just die now.

PS Calling someone Scotch is offensive, its Scottish, biatch.