Green’s Dictionary of Slang

a dismissive excl., implying the absolute unlikeliness of a given event, opinion, etc.

1916		L. Pound ‘Word-List From Nebraska’ in DN IV:iv 277: like fun. Ironical negative. ‘You tried to take her to the dance, didn’t you?’ ‘Like fun, I did.’.
1917		S. Lewis Job 82: ‘Why, I don’t know what you mean.’ ‘Oh no, like fun you don’t—him rubbering at you all day and pussy-footing around’.
1923		H.C. Witwer Fighting Blood 46: D’ye think they made all that fuss for my sake? Like fun!
1932		J. Dixon Free To Love 254: ‘Open that door!’ Her voice was a whip [...] ‘Like fun I will!’ Neil sneered.
1949		R. Park Poor Man’s Orange 39: ‘I’m lost,’ said Motty amiably. ‘Ah, like fun. Never mind, you come inside with me and I’ll give you a cream cake.’.
1953		‘Curt Cannon’ ‘Die Hard’ in I Like ’Em Tough (1958) 24: Shake the monkey? Like fun.
1969		L.R. D’Orsay Story You Can Sell 72: ‘Like fun I will!’ she said. ‘Do you think I’ll let you go alone?’.
1996		T. Wolff ‘Two Boys and a Girl’ in The Night in Question 112: I love to paint. Ask my folks. Every free minute, I’m out there with a brush. Like fun.
2005		J. Callaghan Living Faith, Hope And Love 61: My swain was getting bossy. ‘Why don’t you wear the red outfit? That white pique looks smashing so wear it.’ I thought, Like fun I will!
2008		D. Sedaris When You’re Engulfed in Flames 28: ‘Go ahead,’ we told her. ‘We’ll wait here.’ ‘Like fun you will,’ she said.