Custom Discord In-Channel Activities

I assume this is already the direction discord is taking with their new in channel activities like poker and chess, but I'll just document it here for the sake of it:

It would be a great feature to allow developers to add custom In Channel Activities to the discord interface, via an iframe or the like.

This would allow for nearly endless possibilities for doing things with other people in the channel. It could feel just like walking into a room where your friends are, seeing what they're doing and jumping in right away yourself.

Imagine things like watching videos together, using collaborative tools inside the discord UI, and of being able to make and run your own games inside of discord.