Clonk.de
The official clonk page

CCAN
Download archive with comments, uploading and many display features. (only german)

Clonk Planet Partner- und Projektbörse (CPPP)
Forum with offers and requests for clonk projects. (only german)

Clonk Center
Fanpage with downloads, screenshots and more. (only german)

Clonk Wiki
Freely editable knowledge base for all things Clonk.

Clonk to Connect
Information page with news comments and upate information.