Ocsigen - looks like something comparable to Ur/Web, which is based on the OCaml toolchain and the OCaml language. OCaml has some very nice properties, so this could also be interesting. However, the project gives more of a modular impression with several interoperating parts, and it remains to be seen how well the integration is. What excites me about Ur/Web is the fact that I can really put together a web application with just a handful of files, without much overhead. Also, installing Ur/Web from the source is simpler due to the small number of dependencies. On the other hand, Ocsigen is directly available in Debian, which of course makes the installation much easier.