Mr. Tomkins in Wonderland by George Gamow of Alpher, Bethe, Gamow fame -

https://m.youtube.com/watch?v=WIKOFLRQuc8

That's not advanced undergrad certainly :) .. but I found the following great to learn from. Especially the treatment of momentum and the stress energy tensor really worked for me -

  https://www.amazon.com/First-Course-General-Relativity/dp/0521277035