So, I'm running with this strategy of overcoming dull lesson plans by embracing inspirational stuff and people. For me, this can often hang around concepts of time and space. At the moment I'm reading Gaston Bachelard's The poetics of space.
The series of texts that Walter Benjamin wrote about conceptions of history.
A text by Michel Foucault linked to Gaston Bachelard's work The poetics of space.