a one-night stand
1. a sexual relationship which only lasts for one night, or a person who you have had this type of relationship with I'd rather have a long-term relationship than a series of one-night stands. It's you I love, Karen - Debbie was just a one-night stand.
2. a performance which happens only once in a particular place We're doing a one-night stand in Durham on Monday followed by a couple of nights in Newcastle.