Groupon is the best source for Fenway Park discount and half-price tickets.
You can sometimes find tickets for concerts as well as other events.
Availability varies - but you're always smart to look.
Discount tickets typically become available 2-3 weeks before the event date. Groupon
Fenway Park Seating Maps
Fenway Park's official seating capacity is 35,692 for day games, and 36,108 for night games.
Seat arrangements vary based on the type of event. For example, here is the seat map for Boston Red Sox home games (note that seat prices vary by game and availability - prices may be higher or lower than those shown below):
Fenway Park Seat Capacity Trivia
The biggest crowd ever to pack the park was 47,627 back on September 22, 1935, when the Red Sox played a doubleheader against the New York Yankees, although crowds nearly that large were typical during the early 1930s.
The huge crowds came to an end after 492 people died less than a mile away in 1942 when a horrific fire swept through the overcrowded Cocoanut Grove nightclub. This tragedy led to the creation of more stringent fire codes in Boston and across the nation.