Find any big files:
Do you maintain web server, and you worry if users trying to use your server to download movie file?
find . -size +60M
Find multiple filetypes:
find . -iname *.jpg -o -iname *.gif -o -iname *.pdf -o -iname *.png
Find then execute:
You want to search all .php files and then chmod to make them unreadable by other users?
find . -iname *.php -exec chmod 700 {} \;