One example of irony

Verbal irony (Crooks)

"Come on in. If ever'body's comin' in, you might just as well."

In answer, a clever use of irony in "Of Mice And Men" is the title itself, drawn from a famous poem by Robert Burns: "To a Mouse" where he tells the mouse that the 'best laid plans of mice and men often go awry' (except in scottish), and this is ironic because the core theme of the poem is the schemes and dreams of the characters - Candy, Crooks, Lennie and George in particular - which then fall apart at the end. Simple irony such as 'his name's Lennie, Lennie Small' when in fact Lennie is a huge character, and his strength is his downfall. The name also references his mental size - that of a young child.