The Several Journeys of Reemus by Zeebarf.
The game follows the story of Reemus, an exterminator hunting a giant ant with his purple bear by the name of Liam. By manipulating the environment and (occasionally) Reemus himself, you'll guide him through a series of puzzles that strike just the right balance of logical and abstract thinking. Oh, and there's fantastic music. We think you're really going to enjoy it.
But, as is always the way with the Joystiq Free Game Club, the verdict lies with you. Does it leave you wanting to go on more of Reemus' journeys? Or is one more than enough?
For another look at the Freeware scene, check out BigDownload's Freeware Friday series.