[apgwoz]

Racket has support for serialization of closures and continuations, which it's web server makes extensive use of. It seems like it'd be possible to expose the relevant functions to make that happen, though I have no idea how large the closures actually are once serialized.

[colanderman]

I believe the Racket web server works similarly to the Arc server. At least it did last I checked (back when it was still PLT Scheme).