I’ve admired the work of the folks at Invisible Creature for awhile now. From the Sasquatch Music Festival to the Hurricane Poster Project, Invisible Creature has developed a strong voice in the design world.

Now, you’re invited to join the fun! The Lil’ Happy Invisible Creature S.A.S.E Club is kind of a throwback nod to the days when people actually sent letters to each other (“S.A.S.E” means “self-addressed stamped envelope, by the way).

Here’s how it works:

It’s real simple. Send us a self-addressed stamped envelope and we’ll fill it with goodies. Put 2 stamps on your return envelope and we’ll fill it with more.

However, we thought we’d make it a bit more fun and interactive. Regardless of your artistic ability, we ask that your envelope addressed to us be creatively designed or illustrated. No rules, anything goes – and we’ll post the coolest ones on the Lil’ Happy Twitter page.