Art is other people
Charity:
Consider walking for a charity or cause that resonates with you.
Camera:
Give someone access to a camera and ask them to spend the day taking pictures of everything they find beautiful. (Good activity to have a child do.)
Craft:
Have a craft night with friends, where everyone brings supplies for a different craft, and you all create together. Maybe you could all make ATCs.
Swap:
Host a swap where people can exchange surplus or gently used art supplies and materials.
Messages:
Paint inspiring messages or colourful images on rocks and leave them in public spaces.
Overheard:
Turn snippets of overheard conversation into love letters or mini plays. If a play, record it and share it if you're of a bent to.
Flowers:
Make paper flowers to brighten up someone's day.