I thought I should share my current favourite Ubuntu patch.
While hunting for easy RC bug fixes yesterday, I stumbled across mit-scheme_7.7.90+20090107-1ubuntu1.patch [roughly 9MB]. It contains a Debian .deb to bootstrap the Ubuntu mit-scheme package (bug filed). Nice.
Now, to be fair, Debian has a bootstrapping problem for mit-scheme as well - it requires itself to build, but is currently uninstallable in unstable (although zack's on the case). Having looked at the problem, I think the best thing to do in the long term would be to package mit-scheme-c (which appears to be a superset of the upstream tarball for mit-scheme?