In a year of weekend-long parties, some of the best are saved for last. Here’s what’s going down around town Saturday night.

Bloodfeast Media Party: Machine plays Halloween every night of the year, so expect the ghoulishness to be raised when DJs Mistaker, Mothra and others darken up the electro vibes, with tricks and treats from Karmaloop. 1256 Boylston St., 9 p.m., $15, myspace.com/bostonbloodfeast.