Wizards of the Coast's "Stay at Home, Play at Home" page of free D&D materials and resources
There has probably never been a better time to cajole your family members and far-flung friends into playing D&D. It's a great escape from the strange world we now find ourselves in and a perfect organized activity that involves planning, social interaction, cooperative story-telling, logic and math, creativity, and the imagination.
To make your shut-in days (weeks and months) a little bit more entertaining and fun, WotC has set up a "Stay at Home, Play at Home" section of their Dungeons & Dragons website. There you can find tons of free online tools to assist you in your games: how to play materials, free basic rules, campaigns, encounters, and even activities and coloring books for younger kids. They also have a resource section for ways to play D&D remotely.
(And yes, that's a dragon wearing an N95 mask on the logo. As I said, strange times.)
Image: Program logo