Changing only directory permissions on UNIX recursively

One of those technical buggers that I couldn't figure out, is how to make your command prompt run through a directory and change the permissions (chmod) for only directories in it. Then, just to top it off, do it recursively:

find /dir/to/chmod/all/dirs -type d -exec chmod -R 755 {} \;

That helps us, hope it helps others!  Many thanks to linox.be for the tip!