“šū / شو” is used as an exclamation ("What a ___!", "How ___!", etc.) when followed by a demonstrative pronoun + defined noun, or by an adjective. It can also be used in an exclamatory sense when followed by a verb or verbal phrase.
Using short clips from Lebanese films and TV series, this video shows “šū / شو” being used as an exclamation in various sentences.
Transcriptions and translations of these sentences are available at http://www.lebanesearabicinstitute.com/shu/