It's a guy with multiple personality disorder driving Dr. Becker nuts, as one persona is willing to take the pills while another one is afraid of the pills. This has a funny unfolding as a third persona shows up and Linda is who ends up taking care of the situation.
Bob becomes a Big Brother, although the big part of the title doesn't really fits him. He goes overboard trying to teach culture to the kid and the kid's reaction is typical of what a kid would do in real life.
The weakest link was Chris and Jake annoying the heck out of each other, and even that storyline had its good moments. They really got me confused as to what's the correct way to pronounce 'mayonnaise'.
This is my favorite episode from the whole fifth season, and I highly recommend watching it.