We have so many and do some of the ones already given but I'll tell you a couple of my favorites:
New Years Eve (or day if your not home at midnight): Open every window in the house, let the old year out and a fresh start for the new year in. Living in New England this can get quite chilly - lol.
Easter: Whoever is up first calls all the other family households (doesn't matter how early) and says, "key-key-ka-deee", according to some great-uncle thats the sound the Easter bunny makes.
4th of July: The WHOLE family gets together for a picnic & fireworks on the lake. No matter where or what we all show up. In 1986 I went into labor & had my second daughter a few hours after the fireworks ended.
Christmas: We have a birthday cake for the baby Jesus & sing Happy Birthday.

This is not so much a tradition but just something we do. Three squeezes means 'I love you'. So while waiting in line or in a crowded place with complete silence, you can squeeze someones hand, shoulder , knee, whatever... and tell them you love them. You get the sweetest smiles and usually 3 squeezes back.

teddy