The sbuild suite of programs (wanna-build, buildd and sbuild) are used to build binary packages from source packages. The wanna-build database tracks packages which require building; buildd schedules work from information it gets from the wanna-build database; sbuild does the actual package building. . sbuild can do its work in chroots so both stable and unstable environments can be used on the same machine. Useful for, say, building the latest unstable packages against stable library versions. And by keeping only essential and build-essential in the chroots, you can find the correct build dependencies for a package.
