Sure enough, I did.
Two things in this shot of Matthew Broderick's boss. First is the baseball he's holding -- a reference to the ball Ferris caught at Wrigley Field and later used to turn off his stereo. Also, just over the Mr. Linder's left shoulder is one of those static/lightning globes (I forget their proper name) much like the one found in Cameron's bedroom.
Still in Mr. Linder's office, there's a lamp shade featuring what appears to be some sort of rough sketch on it.
I'm not quite sure what's on the lamp shade, but it's close enough to the lamp shades in Ferris' room that I'm calling this one a movie reference.
And let's not ignore the flower delivery man (Louie Anderson, by the way).
More to come, I'm sure.