For a few years at Princeton and U of I, I was in the habit of making posters for fake talks and hanging them around the physics department on April Fool's Day. Some of my favorites included:
Applications of Non-Linear, Non-Homogeneous, Non-Solvable Partial Differential Equations
and
Theoretical Biophysics Colloquium
Insane in the Membrane:
Insane in the Brain?
Prof. B. Real
Cypress Hill University