The Big Bang Theory Episode 4.14 The Thespian Catalyst

Sheldon has agreed to take part in a short lecture series at the university. After completing his first lecture, he is shocked to find out just how much the students hate him as a teacher. Amy tells him that teaching is a performing art and suggests to Sheldon that perhaps her best friend, Penny, could share some of her acting skills with Sheldon to make him a better teacher and learn to connect with his audience better. Sheldon goes to Penny and asks her to give him some acting lessons. Sheldon doesn't take Penny's direction well and is an awful actor yet he thinks he is a brilliant playwright and improvizationalist and decides to use his newfound skills on his students.

Koothrappali is feeling down about not having a girlfriend and Bernadette reasures him that someone as great and cute as him will not stay single for long. Soon Koothrappali realizes he ha as crush on Bernadette and we see several daydreams with he and Bernadette. The final one ending in a Bollywood style musical number.