Some kids went trick-or-treating to my deaf grandparents and hilarity ensued (my grandpa didn't remember what Halloween was). I wasn't there sadly and I didn't do anything in particular. As in most good Catholic countries, Halloween here is just seen as a spooky commercial alt of Carnevale, so it hasn't reached the popularity it has in the US yet.
We just have Day of the Saints (yesterday) and Day of the Dead (today) during which you go put some flowers on the graves, say some words for your dead relatives and eat ossa da morto (traditional frosted cookies, literally 'bones of the dead'). We don't have the Pre-Columbian traditions the Mexicans have, so it wasn't much fun before Halloween was imported.