How far David Letterman has come in his interactions with reality stars since the days when he'd require visiting Survivor castaways to stand in quarantine, disinterestedly lobbing questions about insect-ingestion from a contagion-safe distance of 15 meters. Now, they climb right into the chair next to him, just like real stars!

Still, you can't expect him to do the necessary homework, as became painfully obvious grilling The Hills star L.C. Conrad last night about her career accomplishments. Armed with only a 5x7 cue card bearing topical keywords ("Laguna," "Spencer," "Teen Vogue," "Frenemies," etc.), Letterman fumbled through the dialogue like an ornery convention attendee desperately trying to find common ground with the three-diamond escort/aspiring stylist whose services he'd secured for the night.

• Late Show

Tags: clips | david letterman | lauren conrad | mtv | reality tv | the hills