 " Debasement Tapes " features a guest appearance by Paul Rudd . A friend of series creator Rob Thomas and Enbom , they had hoped that Rudd would guest star on the show since its inception in 2004 . Announced four months prior to the episode 's airing , his appearance was highly anticipated by Thomas , who had high hopes for the pairing of Rudd and Enbom . In its original broadcast , the episode received 1 @.@ 85 million viewers and mostly positive reviews from television critics , with Rudd 's performance and the various subplots being generally well @-@ received , although some disliked the main mystery . 
