Don. Knotts. He was in two episodes during the "New Scooby-Doo Movies" series, and he is AMAZING in them. The episode "Guess Who's Knott Coming to Dinner" is officially the funniest thing I've ever seen, both for Knotts' performance, and for the endless gags where everyone's pretty much acting like Shaggy. Except Shaggy. lol I LOVE that movie, and I love Don Knotts.

Other guest stars were of course great too, but Don is just easily my favorite.

More than one really there was The Addams Family,Sonny & Cher,Don Knotts,basically anyone that guest starred in the New Scooby Doo Movies..

Once again, I have to concur with the choices made. Bringing in all of those wonderful, talented, highly appropriate guest stars for the New Movies was sheer genius. Don is incredible and hilarious; I love everything I've ever seen him do. MortalAnonymous is right; his role in "Guess Who's Knott Coming to Dinner" is totally priceless, and it's just awesome overall.

Cass Elliot in the 'New' scooby doo movies

Hex Girls are the best

And throwing in random guests almost never improves things.

(With very few exceptions…)