If Psychonauts is not already part of your PC game library, you can add it free of charge right now. The Humble Store is giving away the Double Fine game for free, but you'll have to act quickly to claim your copy.

Grabbing the game is as simple as adding it to your cart--do so here--and checking out. You'll need a Humble account in order to do so, but you can sign up for free if you don't already have one. The game is redeemable on Steam, which you'll also need in order to play. Psychonauts will remain free until 10 AM PT / 1 PM ET / 6 PM BST on Saturday, September 16.

Psychonauts is one of the most beloved games in Double Fine's catalog. It's an action-adventure game in which you play as a young psychic who explores the minds of other characters, which serve as the game's various worlds. It was originally released back in 2005 to a good deal of acclaim before being updated on Steam in 2011 with features like cloud save support.

A sequel was announced back in 2015 and was successfully crowdfunded. We saw new Psychonauts 2 gameplay footage earlier this year, and it's due out in 2018. Earlier this year, we also got a VR spin-off, Psychonauts in The Rhombus of Ruin.