Season 5
In season five, Penny and Leonard's relationship is relaunched in full "beta test" mode, while Sheldon, Howard, and Raj discover the feminine mystique is something that cannot be easily graphed or calculated. As Sheldon makes begrudging amendments to his "Relationship Agreement" with his "friend-who-happens-to-be-a-girl" Amy Farrah Fowler, Raj contemplates an arranged marriage, and Howard is all-systems-go for both is NASA space launch and wedding to the spirited Bernadette.
Episodes
1 The Skank Reflex Analysis Sep 22, 2011 
2 The Infestation Hypothesis Sep 22, 2011 
3 The Pulled Groin Extrapolation Sep 29, 2011 
4 The Wiggly Finger Catalyst Oct 6, 2011 
5 The Russian Rocket Reaction Oct 13, 2011 
6 The Rhinitis Revelation Oct 20, 2011 
7 The Good Guy Fluctuation Oct 27, 2011 
8 The Isolation Permutation Nov 3, 2011 
9 The Ornithophobia Diffusion Nov 10, 2011 
10 The Flaming Spittoon Acquisition Nov 17, 2011 
11 The Speckerman Recurrence Dec 8, 2011 
12 The Shiny Trinket Maneuver Jan 12, 2012 
13 The Recombination Hypothesis Jan 19, 2012 
14 The Beta Test Initiation Jan 26, 2012 
15 The Friendship Contraction Feb 2, 2012 
16 The Vacation Solution Feb 9, 2012 
17 The Rothman Disintegration Feb 16, 2012 
18 The Werewolf Transformation Feb 23, 2012 
19 The Weekend Vortex Mar 8, 2012 
20 The Transporter Malfunction Mar 29, 2012 
21 The Hawking Excitation Apr 5, 2012 
22 The Stag Convergence Apr 26, 2012 
23 The Launch Acceleration May 3, 2012 
24 The Countdown Reflection May 10, 2012