Ben's videos are some of the most interesting content on Youtube. The build an 8-bit computer from scratch tutorial has been around this site a few times, as has the 6502 series. But what really gets interesting are these peripheral videos where he digs into a specific system or concept. His videos about how error correction works were a real eye-opener for me. It's the right level of zoomed in.
I wish more devices simply used RxTx (or COM/RS-232) so that the protocol was defined inside the character payload instead. Simplicity is worth sacrificing bandwidth for.