This plugin will show a random XKCD comic each time IntelliJ is opened, or when a new project has been launched. (This can be used instead of the 'tips' dialog IntelliJ normally opens when starting or opening a project.
DylanMeeus/IntelliJ-Xkcd-Startup
Shows a random XKCD comic when an IntelliJ project is opened
JavaGPL-3.0