Place for P2P Michel in Berlin

For everyone from Berlin, it would be great if you can offer a sleeping place for some days/weeks to Michel Bauwens:

Dear friends, my name is Michel Bauwens and some may know of my work for the P2P Foundation. From April to June I have to stay in Berlin but with my very limited finances, lodging is a bit of an issue. I am therefore looking for any free or cheap lodging opportunities, they can be in chunks of days or weeks as well. Thanks for sending any hosting opportunities my way. you can also email michel at p2pfoundation dot net.