Final answer:
In the episode 'Casino Night' of the television series 'The Office', Ryan Howard orders Kelly Kapoor a Coke at the fictional Dunder Mifflin casino night event.
Step-by-step explanation:
The question "What drink does Ryan order for Kelly on casino night?" pertains to an event from the television show 'The Office', which falls under the category of Arts, specifically in television or popular culture studies. This query does not relate to any educational subject matter like Mathematics or Biology, but instead to elements of a televised series' storyline and characters.
In the episode titled Casino Night, which is the twenty-second episode of the second season of 'The Office', Ryan Howard orders Kelly Kapoor a Coke. This event takes place in the context of a casino night fundraiser hosted by the characters of the show within their office workspace. It's a minor detail, part of a larger narrative that explores the interpersonal relationships between characters and the comedic scenarios they find themselves in.