Photography is allowed in MLB/NBA/NHL and NFL games.
Here are the rules for the NHL:
http://www.theaircanadacentre.com/contact/FAQ.asp#17
Can I bring my camera to an event?
For most events, the use of flash photography and professional equipment, video or audio recording is not permitted. Small point-and-shoot cameras are generally permitted inside the building. We reserve the right to confiscate any tape or film that is used during an event.
NBA: Use of flash photography is prohibited. Video cameras are permitted, but the use of still photos or video footage for commercial purposes without written permission from the NBA is strictly prohibited.
NHL: Video cameras are not permitted. Non-flash photography is allowed; however, if the lens is detachable it must not exceed 75mm.
NLL (Toronto Rock): Video cameras are not permitted. Non-flash photography is allowed; however, if the lens is detachable it must not exceed 75mm.
Concerts and Live Events: As the camera policy for each event varies, we recommend that fans contact Fan Services at (416) 815-5982.