Strip in question: http://www.gocomics.com/peanuts/1953/11/02
This is a gag that Schulz will return to in later years, the character who is a day late in celebrating a holiday. April Fool's is a particularly fun day to do this with, since victims tend to be off their guard.
For the time being, I'm going to just link to the relevant gocomics.com page for the comic under discussion. I might inline them from a local copy eventually, which I think would be provided for under fair use, and anyway doesn't seem to have hurt the Comics Curmudgeon any. But maybe there's some aspect of his situation I'm not aware of. Certainly hosting the images from this site makes bandwidth a bit more of a concern.
Did I mention I like his egg paintings
47 minutes ago