What are some instances that you can remember of characters appearing outside their normal settings?

I know of:

-El Capitano showing up at the Prevert's house selling vacuum cleaners.
-Mrs. Prevert getting shot by El Capitano because her daughter "died of embarrassment".
-Mr. Shidtler showing up in Chris' closet to teach him about getting ready in the morning.
-I also remember Mrs. Prevert having to go on a run by the Coach because she didn't have her mother there to get her out of it.

It seems like the last two seasons had more of these instances than the earlier seasons.