Delving deeper, we've got number 080.
I’ll be back. To terminate those pesky rats.
#080 How to put LEDs in Lego figures
article
If you’ve still got some bits of Lego laying about somewhere from your days as a young Lego-builder and you fancy moving up in the world of Lego, then why don’t you try butchering your old Lego to stick little LEDs into them?
This extremely helpful article tells you how to do exactly that, in an extremely easy to understand way.