From now to April 7th. There are two events: Clearance Cash Back event and Keep on Giving.
Check the detail:
Event #1 - Clearance Cash Back!: Purchase any 5 clearance items and you're automatically entered in a random drawing for 5k Maple Points! 20 winners will be chosen.
Event #2 - Keep on Giving!: Players who gift any item to friend will enter into a random drawing to win a free MapleStory plushie! 20 winners will be chosen.
Rewards will be given out mid April, during the server maintenance. Exact date will be announced shortly.