Vasectomy is a surgical procedure for male sterilization, and consequently, birth control. During the procedure, the vasa deferentia of a man are severed, and then tied/sealed. This prevents sperm from entering into the seminal stream (ejaculate). You can watch a video how the procedure is done here.
From Cleveland Clinic YouTube channel: A urologist talks about the increase in the number of vasectomies he does this time of year. "Guys get it done, then watch the NCAA Basketball tournament all weekend long." The procedure takes 5-10 minutes. Patients need to ice the area for 2-3 days.
The NCAA Men's Division I Basketball Championship is a single-elimination tournament held each spring in the United States, featuring 68 college basketball teams, to determine the national championship in the top tier of college basketball. The tournament, organized by the National Collegiate Athletic Association (NCAA), was created in 1939 by the National Association of Basketball Coaches, is held mostly in March, and it is known informally as March Madness (source: Wikipedia).
Private urology practices advertise on TV their "Vasectomy Madness" campaigns:
CNN RidicuList with Anderson Cooper: Vasectomy and free pizza (video):