If you really want to see the online source, it is in Bylaw 17.12.5.3 (pages 273-274) in the NCAA Division I Manual:
http://www.ncaapublications.com/productdownloads/D111.pdf.
The game limit is 34. The following games do not count against the 34-game limit, but do count in official NCAA Statistics and Records--
* Hockey Hall of Fame Game--a single fundraising game conducted every year
* Ice Breaker Tournament--a single 4-team, 2-game tournament conducted every year
* Any game played in Hawaii or Alaska--only by a school from outside those states against a school inside that state
* Conference championship tournament
* NCAA tournament
Also not counting against the 34-game limit, and not counting in NCAA statistics--
* Home game against a foreign team, such as a Canadian University or a foreign national team--limit one
* One away tour against foreign teams--limit one tour every four years.
* US National Teams--a single game per year against any US National Team (e.g., Olympic Team, World Junior Team, Under-18 Development Team, etc.)
* "Alumni game" (exhibition of current players vs alumni of the school)--limit one
* Certain other charity game activities are also permitted, but generally may not involve the entire team.
Typically, a team will play about 34-38 regular-season games plus 1-2 exhibitions. Teams rarely play more than 8-10 playoff games, so I would be surprised if any team has managed to play 50 games in a season (counting exhibitions) since the basic limit was lowered from 38 to 34.