Joke comprehension has been decomposed into surprise registration followed by a coherence stage, involving frame-shifting (retrieving a new frame from long-term memory to reinterpret information in working memory). We examined this view by recording event-related brain potentials (ERPs) from adults reading one-line jokes or non-joke controls with equally unexpected endings. Joke and non-joke ERPs differed in several respects depending on participants' ability to get the joke and contextual constraint. In good joke comprehenders, all jokes elicited a left-lateralized sustained negativity (500-900 ms), indexing frame-shifting, low constraint jokes elicited a frontal positivity (500-900 ms), and high constraint jokes elicited an N400 and later posterior positivity. By contrast, poor joke comprehenders showed only a right frontal negativity (300-700 ms) to jokes. This pattern of effects does not map readily onto a two-stage model of joke comprehension.