When I teach allusions with my students, I describe them as "inside jokes that YOU don't get." Then I try to expose them to as many allusions as possible, so that they can "get in on the joke."
This PowerPoint covers the definition of an allusion in literature, and covers many common allusions found throughout literature. The allusions are broken down by type: Historical, Mythical, Biblical, and Literary. Use of the presentation will broaden students' knowledge of commonly referenced allusions, as well as help them better understand their study of literature. It also enhances their writing, as they are encouraged to use the allusions themselves.