At the end of the fourth season, at the Premiere, the outside sign advertising a movie called Now She's Carly, referring to Miranda Cosgrove who goes from playing Megan to Carly in iCarly.
In the episode where Josh gets mad at Drake for making him miss his chemistry exam, Drake comes into the house with a green sit and bounce to make Josh feel better, almost through the entire scene you can clearly see the reflection of all the stage lights in the shiny green sit and bounce.