The Polya seminar was first started by Ravi Vakil, and his excellent webpage contains much useful information.
The seminar is named after George Polya (1887-1985), a great mathematician and problem solver.
Not just math majors have done well; many recent winners have come from nearby disciplines, including physics, computer science, and engineering.
Completely solving even one of the twelve problems is a significant achievement, and in almost all years would place you well above the median.
The departments of teams finishing in the top 5 also get cash awards; we've done well on this count in the past, and those awards have been used to support math activities for undergraduates.
Regular meetings will be on Mondays from 6- in 380Y.
But if you do sign up for the course, then to get credit it is expected that you will attend all of the seminars, and take part in presenting solutions from time to time.
The Putnam is a challenging opportunity for you to test your mathematical mettle.