How can I slurp a subtree?

I am sure I have read something about a sort of robot which basically
grabs a subtree, i.e., performs a series of queries without getting 
documents in a different path from the first one chosen.

I know it is not difficult to write a script, but I hope that the original
program is site-friendly, so that I don't have to think about it :-)

Does anyone have a pointer?

.mau.