mouser
Business of Hockey
While it is fairly likely to be upheld as fair use - I am not aware of any courts actually ruling on the matter.
However, the decryption tools which would be needed to make that backup are illegal under the DCMA.
edit: I guess Mouser beat me to it - that's what I get for actually taking a night off these boards and going to a game, although I'll guess that I enjoyed it more than Mouser .
If you're really interested in reading, here's the most recent ruling I'm aware of the topic. 2004 MGM vs. 321 Studios
http://w2.eff.org/IP/DMCA/MGM_v_321Studios/20040219_Order.pdf
Ruling acknowledged fair use remains in effect, but that it doesn't apply to the DMCA barring distribution of decryption bypassing tools because fair use is an affirmative defense to copyright violations, while the DMCA ban on decryption tools in this case didn't involve claims of actual copyright violations.
Also, I'd like to suggest in the next CBA that games be reduced from 60 to 40 minutes.