Another Pinkie's Pride clip has surfaced over on a Youtube channel called "Geekscape TV". Once again, it expands on Cheese Sandwich. They also have an updated synopsis to go with it. Head on down below the break for both!
Thanks to Marxa for the heads up!
(Update: Second clip added and get some high resolution images over at Geekscape!)
New synopsis:
"Pinkie Pride" — An elated Pinkie Pie is planning the biggest and best "birth-iversary" party ever for Rainbow Dash, but when another party planning pony named Cheese Sandwich rides into town, plans change. Soon, everypony is so excited about Cheese Sandwich's party that they forget about Pinkie Pie, but her pride won't let her go down without an official "goof off," on "My Little Pony Friendship Is Magic,"Saturday, February 1 at 10:30 a.m. ET/ 7:30 a.m. PT on the Hub Network.