Yes, and then I found this wiki page about the topic and I still am confused: https://en.wikipedia.org/wiki/Partial_evaluation

Can anybody explain like I'm 5?

Not like you're five, but if you're interested: the standard introduction is still 'Partial Evaluation and Program generation', which is freely available http://www.itu.dk/~sestoft/pebook/pebook.html

Here's the simplest code I could come up with for 'dynamic' partial evaluation, showing interpreter->compiler but not the higher projections: http://wry.me/~darius/writings/peval/

Dan Piponi has a nice introduction to Futamura's projections in his blog: http://blog.sigfpe.com/2009/05/three-projections-of-doctor-f...

I think it's trying to tell you you really like Futurama.

Obviously the first Tales of Interest episode, where the Professor uses the What-If machine to find out what would have happened if he had invented the Finglonger.