Watch The Big Bang Theory Season 9, Episode 3 The Bachelor Party Corrosion Online

The guys' science skills are put to the test when they get a flat tire during Leonard's bachelor party weekend in Mexico. Also, the girls force Penny to finally tell her family that she eloped with Leonard. Leonard and Sheldon are brilliant physicists, the kind of "beautiful minds" that understand how the universe works. But none of that genius helps them interact with people, especially women. All this begins to change when a free-spirited beauty named Penny moves in next door. Sheldon, Leonard's roommate, is quite content spending his nights playing Klingon Boggle with their socially dysfunctional friends, fellow CalTech scientists Wolowitz and Koothrappali. However, Leonard sees in Penny a whole new universe of possibilities... including love.