Write a fic, make an icon, make a vid, or make a fanart for someone. Buy someone paid time or userpics. Leave someone a nice comment. Say something nice about something fannish someone else loves. Say something nice about something fannish you love and encourage squee (and squee on someone else’s post if they make one!). Offer to beta for someone. Offer to donate five dollars to the charity of someone's choice. Send flowers to an online friend in a different city. Buy someone you know online a present. Or a virtual present. Plant a tree or a flower in someone's honor and take a picture of it and post it to your LJ. When somebody cuts you off at work, wish them well and hope they get where they’re going safely. Make somebody a friendship bracelet. Or a construction paper heart. Call someone you love and tell them so. Or anything else you can think of!
To find out more about it, check out More Joy Day on Fanlore
I think this is a fabulous thing, especially this year! Spread the love, my friends!