Lena (Verbal Irony)
Lena is scathingly ironic when she responds to Leo's cry that the Happiness Machine is finally finished. She says, "His wife is nervous, she's gained ten pounds, she'll need new clothes, look! Sure - the machine is ready!" (55). Her irony reveals how against the machine she is because she knows it is not real happiness.
Age (Dramatic Irony)
The children of the town are convinced old people were never young. Douglas says, "I never thought of that. That's brilliant! Old people never were children!" and Tom replies, "And it's kind of sad... There's nothing we can do to help them" (79). Of course, the glaring irony here is that both will grow old, and indeed, are growing older every second of the summer.
Lavinia and the Lonely One (Situational Irony)
Bradbury presents terrifying situational irony when Lavinia believes she is being followed by the Lonely One in the ravine and exerts all of her effort to run away from him. She swears she can hear him and sense him, but the irony is that the Lonely One is in her house the whole time.
Grandma's Cooking (Situational Irony)
Aunt Rose comes to visit and sets Grandma's kitchen to right. She gives Grandma glasses so she can see, buys her a cookbook, and reorganizes her disastrously chaotic kitchen. However, the irony in this is that Grandma does NOT become a better cook. Her food is terrible and all the joy has gone out of the ritual of eating for the family.
