Thanks again to Raymond (Wordsummit) for the suggesting this one.
I put together some links for this one, to see how long it takes. Bit too much to do it for each idiom, unfortunately, even as cursorily as I did here. Maybe I’ll add just one or two links for each one to serve as a reminder that there exists lots more information.
⇒ chinese-tools.com: chengyu dictionary
⇒ Bright Hub Education: Ten Chinese Idioms to learn
⇒ teachmechinese: Chinese idioms involving goats and monkey
⇒ International Language Centre (Hong Kong)
⇒ youtube search