I think a fun bit is to make a reference to two things, one of which is rather obscure and the other is comparatively well-known, and then, if prompted to explain, to treat the more obscure bit as if it is sufficiently common knowledge as to not need explaining, whilst acting as if the well-known thing is in need of clarification.
For example, one could post "The Old English vision poem The Dream of Darude." If someone asks for an explanation, one would talk about The Dream of the Rood and leave Darude unremarked upon.