Kurt an Blaine Go to Prom Together in Glee Season 2, Episode 20: "Prom Queen"
Now that they were officially a couple, Kurt and Blaine started engaging in all the adorable coupley things we’d expect. Top among those? Go to prom together! The evening wasn’t all smooth sailing — by any stretch of the imagination — but Blaine’s support helps Kurt get through yet another tough bullying situation.