Raising Hope

Conan O'Brien on "How I Met Your Mother"

Martin Short and Kal Penn delivered laughs this season, but Conan O'Brien's visit wins for its "blink and you'll miss it" subtlety. The comedian, who skulked through the background at MacLaren's on Feb. 20, apparently won the walk-on role ... more in a charity auction. That means instead of being paid for the cameo, he actually paid for it.

Bing: More about 'How I Met Your Mother' | Watch episodes and clips

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"How I Met Your Mother" airs Mondays at 8 p.m. ET/PT on CBS.

(AP)