The National Senior Games consist of 19 sports, the large majority of which feature multiple offerings.  Most of the sports are played by individuals, pairs, or small relay teams, while three events are full team sports.  The sports are:
•    Archery
•    Badminton
•    Basketball (3-on-3)
•    Bowling
•    Cycling
•    Golf
•    Horseshoes
•    Pickleball
•    Race Walk
•    Racquetball
•    Road Race
•    Shuffleboard
•    Softball (team)
•    Swimming
•    Table Tennis
•    Tennis
•    Track & Field
•    Triathlon
•    Volleyball (team)
The only universal requirement for all male and female participants is that they are at least 50 years old.  Age divisions exist for individual, doubles, and relay competitions are as follows:
•    50-54
•    55-59
•    60-64
•    65-69
•    70-74
•    75-79
•    80-84
•    85-89
•    90-94
•    95-99
•    100+
For team sports, the following age divisions exist:
•    50+
•    55+
•    60+
•    65+
•    70+
•    75+
•    80+ (3-on-3 basketball only)

For all non-individual competitions (doubles, relays, team sports), teams are classified into a division based on the age of their youngest player.  So, if a 3-on-3 basketball team had players aged 68, 72, and 63, they would play in the 60+ division.  A full list of standards and rules can be found here:  http://www.nsga.com/media/documents/rules/2013-nsga-games-rule-book.pdf