Some of you already know that I'm mexican and proud, and Dia de los Muertos (Day of the Dead) is a very important tradition for me. While it is also celebrated in other parts of Latin America I am only familiar with the traditions we have here, so I'm really sorry for not being able to represent everyone
But feel free to leave me a comment with your own traditions, I would love to read about them 
In case anyone is interested some years ago I published a more or less detailed explanation on ofrendas (offerings) complete with photos. Also, I shall warn you that I consider myself a purist, and while I appreciate everyone's efforts to make art inspired by Dia de los Muertos there's some things that simply don't go with the spirit of this date, and I won't include them in this feature... for example, cobwebs and spiders belong to Halloween, and Dia de los Muertos is a happy and colorful date, not dark and Gothic.
Dia de los Muertos is a date to remember that death is a part of every day's life. So skeletons are depicted doing common things and just living happily.
It is a colorful day full of flowers, food, candles, dancing and singing. Most of the celebrations are held in cemeteries, people go tidy and decorate their beloveds' tombstones to receive them for this day. We remember the dead, keep them present, laugh and eat with them. It is a great way to accept the passing of someone loved, while at the same remember them dearly and happily, we remember how much we loved them and all the good moments we spent with them, not the bad or sad things. In essence, it is a celebration of life, love and happiness.
