From 7pm Friday, March 23 until 7pm Sunday March 25 you can work countries around the world on HF SSB. The goal of this contest is to work as many prefixes as possible, with more points earned for countries on a different continent than you. The exchange for this contest is very simple, 59 and a serial number. Start with one and give each successive contact the next serial number in line.
CQ SPX SSB contest details