University physicists Leonard and Sheldon know whether to use an integral or a differential to solve the area under a curve. But they don’t have a clue about girls. Or dating. Or clothes. Or parties. Or having fun. Or, basically, life.

So when a pretty blonde named Penny moves in the apartment across the hall, the guys decide to get an education outside of the classroom. Boys, you have a lot to learn.

With series creators Chuck Lorre and Bill Prady concocting the right mix of logic and lunacy and stars Johnny Galecki and Jim Parsons turning geekdom into Phi Beta fun, The Big Bang Theory is big on laughs. And life.

All 23 episodes from the second season of the US comedy series revolving around two university physicists, Leonard (Johnny Galecki) and Sheldon (Jim Parsons) and their beautiful, free-spirited neighbour Penny (Kaley Cuoco). Episodes are: 'The Bad Fish Paradigm', 'The Codpiece Topology', 'The Barbarian Sublimation', 'The Griffin Equivalency', 'The Euclid Alternative', 'The Cooper-Nowitzki Theorem', 'The Panty Pinata Polarization', 'The Lizard-Spock Expansion', 'The White Asparagus Triangulation', 'The Vartabedian Conundrum', 'The Bath Item Gift Hypothesis', 'The Killer Robot Instability', 'The Friendship Algorithm', 'The Financial Permeability', 'The Maternal Capacitance', 'The Cushion Saturation', 'The Terminator Decoupling', 'The Work Song Nanocluster', 'The Dead Hooker Juxtaposition', 'The Hofstadter Isotope', 'The Vegas Renormalization', 'The Classified Materials Turbulence' and 'The Monopolar Expedition'.

The complete fourth season of the US comedy series revolving around a pair of socially dysfunctional university physicists. Leonard (Johnny Galecki) and Sheldon (Jim Parsons) seem content enough working at physics during the day and playing computer games and hanging out with their fellow scientists and social recluses, Howard Wolowitz (Simon Helberg) and Rajesh Koothrappali (Kunal Nayyar), at night. That is, until beautiful, free-spirited Penny (Kaley Cuoco) moves into the apartment next door and opens up the possibility of a whole new world of love. Episodes are: 'The Robotic Manipulation', 'The Cruciferous Vegetable Amplification', 'The Zazzy Substitution', 'The Hot Troll Deviation', 'The Desperation Emanation', 'The Irish Pub Formulation', 'The Apology Insufficiency', 'The 21-Second Excitation', 'The Boyfriend Complexity', 'The Alien Parasite Hypothesis', 'The Justice League Recombination', 'The Bus Pants Utilization', 'The Love Car Displacement', 'The Thespian Catalyst', 'The Benefactor Factor', 'The Cohabitation Formulation', 'The Toast Derivation', 'The Prestidigitation Approximation', 'The Zarnecki Incursion', 'The Herb Garden Germination', 'The Agreement Dissection', 'The Wildebeest Implementation', 'The Engagement Reaction' and 'The Roommate Transmogrification'.

The complete third season of the US comedy series revolving around two university physicists, Leonard (Johnny Galecki) and Sheldon (Jim Parsons), their beautiful, free-spirited neighbour Penny (Kaley Cuoco), and their friends Howard Wolowitz (Simon Helberg) and Rajesh Koothrappali (Kunal Nayyar). Episodes are: 'The Electric Can Opener Fluctuation', 'The Jiminy Conjecture', 'The Gothowitz Deviation', 'The Pirate Solution', 'The Creepy Candy Coating Corollary', 'The Cornhusker Vortex', 'The Guitarist Amplification', 'The Adhesive Duck Deficiency', 'The Vengeance Formulation', 'The Gorilla Experiment', 'The Maternal Congruence', 'The Psychic Vortex', 'The Bozeman Reaction', 'The Einstein Approximation', 'The Large Hadron Collision', 'The Excelsior Acquisition', 'The Precious Fragmentation', 'The Pants Alternative', 'The Wheaton Recurrence', 'The Spaghetti Catalyst', 'The Plimpton Stimulation', 'The Staircase Implementation' and 'The Lunar Excitation'.