April: Spring-related Party and Funny Hat Week 2015
May: The Fair 2015
June: Time Trekker Party (This time, a paradox has shown up, and it's affecting past, present, and future)
July: Gravity Falls Party
August: Operation: Whiteout (Herbert attempts to blind out the penguins on Club Penguin Island, instead of using all of the sun's power to black out the island)
September: Elite Penguin Force Seasonal Meeting (event, every spring, summer, etc) / Operation: Anchovies (minor operation) / Return of the Time Trekker (more paradoxes!)
October: A GOOD HALLOWEEN PARTY, Pizza Party (event), World Food Day
November: Like OP, Card Jitsu Party and a Operation: Ninja, and an unnamed event
December: EPF Seasonal Meeting / Holiday Party 2015: The Christmas/Holiday Trekker (the paradox trekker had it's own GLaDOS-like AI installed into it, and he dresses up as Santa for the Christmas season)
January 2016: ????, ????, January FoOlS paRtY (CP's apology for stopping April Fools due to low popularity)!
(P.S. The time trekker is now a mascot who visits regularly during parties)
I feel like there should be at least one party, and two events- one before the party, and one after so we don't get too bored of the same Club penguin experience between parties.