"When Bert's Not Here"
It's telling that Ernie is sad and lonely without Bert, whereas the first words that Bert has to say about Ernie's absence are, "This is great!"
There's another sketch in which Bert is away and Ernie pretends Bert's here by drawing a picture of him and propping it up in Bert's bed. It's available on YouTube as a bootleg, but for some reason the uploader added annotations that are apparently supposed to be funny. I don't get why some people feel the need to parody Sesame Street. Some of the parodies are good, like Avenue Q, but Sesame Street is so funny and satirical on its own that, to me, it seems like gilding the lily.
In the second sketch, Bert says that Ernie is sleeping over at the Count's. Really? Has he forgotten what happened at the last sleepover they had with the Count?
"Bert's Blanket" is an homage (or at least contains an homage) to "The Leader of the Pack" by the Shangri-las, an irresistibly melodramatic song very dear to my heart. The homage becomes most apparent with the "'Get the picture?' 'Yes, we see'" exchange.