Martha Bannister didn't mean to make up a boyfriend, but with her marriage crazy mother hounding her and her smug sister's perfect wedding fast approaching, she felt backed into a corner. It was too easy – giving him a name (Kevin), telling her mother about his
annoying bathroom habits (which of course, she secretly found adorable), gossiping with her sister about his sweet moments of pure goofiness (much sweeter than her sister's fiancee). It was the perfect solution to an unsolvable problem – she was able to satisfy her family
without having to find a second-rate man that she could date until she managed to stumble across the real thing. And if she sometimes wished Kevin actually existed, it was only in her most maudlin moments –other than that, the situation was pure bliss.
(your hook starts here)
Most people call Martha "Martz." She's a 26 year old beauty editor who lives in New York, has brown hair and green eyes, and hasn't had a real date since college. And this morning, she woke up in bed with her imaginary boyfriend.
Develop this with more about what happens next and you've got something pretty funny.