Adding Blocks to a node.

Hi,
I am trying to develop a new content type which should allow the users to add blocks to a node. I have actually generated some dynamic blocks. Now I want a node creation page where in the users can create a node/page by just adding the already existing blocks to the node.

(They don't neccesarily have to be blocks, any dynamic PHP code units which return proper html. )

Any ideas if there is an already existing module which allows it, or should I write a new content type or can I use the CCK by writing something such as a "Block Field"

Any help is greatly appreciated..

Thank you.