Mad About You - Season 5 Episode 23 -

Jamie is suffering from sleeplessness because she drank four cups of tea full of coffeine while studying for a test. Restless and board, Jamie urges Paul to spend the night awake with her which leads them to an all-night adventure in the building, from the basement to the rooftop, which ends with a tango together with John Astin, if that's who he really is.