How to make per- http Request cache in ASP.NET 3.5

We using ASP.NET 3.5 (Controls-based approach) and need to have storage specific for one http request only.

Thread-specific cache with keys from session id won't work because threads are supposed to be pooled and therefore I have a chance to have data from some previous request in cache, which is undesirable in my case. I always need to have brand new storage for each request available through whole request.

Any ideas how to do it in ASP.NET 3.5?