Nickelodeon’s Valentine’s Day preschool marathon is as follows (all times are ET/PT):

9:00 a.m. - Dora the Explorer “The Grumpy Old Troll Gets Married” PREMIERE

The Grumpy Old Troll is getting married to Petunia (voiced by Carol Kane) and everyone is a part of the wedding. Everything’s almost ready, except the Grumpy Old Troll forgot to pick up the rings from his Grandma’s house. Dora and her friends must dance the “Troll’s Happy Dance” to make it across the Flowery Garden; count with the Wedding Bells and find the rings at Grandma’s house so the Grumpy Old Troll can have his w...