Ron Pearlman is a fantastic VA and actor. 

Tom Kenny (Voice of SpongeBob Squarepants, the mayor from The Powerpuff Girls and countless other characters.) sings Take me Out to the Ballgame.

From the 2013 documentary, "I Know That Voice".

Howard Morris, who voiced Jet Screamer from The Jetsons and Wade Duck from Garfield and Friends, is probably best known as Ernest T, Bass from The Andy Griffith Show.

Mel Blanc is a scream on-screen lol.

Here is an apperance by Christine Cavanaugh who voiced Chucky from Rug Rats and many other things. This is sort of a two for one as well because the red head kid is Danny Cooksey and has done a ton of voice over work.

 

debi derryberry (former voice actress for jimmy neutron) was actually in an episode of "hey vern, it's ernest!" she's the girl talking to the robot at the 8:19 mark of the video.

June Foray and Bill Scott. Voices of Rocky and Bullwinkle.