It's not something anyone's really interested in discussing, and most seem to think it's not likely to happen, but it remains a possibility: A lockout or a strike may prevent some or all of the 2011-12 NHL season from taking place.
When there was a lockout in the 2004-05 season, fans were disappointed to be without NHL hockey, but the fact that the Stanley Cup wasn't awarded didn't seem all that notable. The NHL has somehow appropriated the trophy and made it virtually their own, so the fact that they didn't have a season meant that there was no champion to whom the Cup should have been awarded. That's not the Cup's purpose, though; it was initially a challenge cup governed by two trustees intended to promote hockey in Canada. Its current role as the NHL's championship trophy certainly serves that goal--I can think of no better way to give a trophy exposure than this--but if there's no NHL season, why shouldn't the Cup still be awarded?
Well, it turns out that it could still be awarded, as per the terms of a settlement reached in 2006 between the League and a couple of highly motivated hockey-lovers from Toronto. Basically, the terms dictate that the Cup's two trustees (currently Scotty Morrison and Brian O'Neill) have the discretion to offer the trophy outside of the NHL if the League cancels or loses yet another season. Hopefully that means we won't have to see something like this again.
So, in the unfortunate event that the 2011-12 season is cancelled, which league should have the privilege of playing for the Dominion Hockey Challenge Cup (Lord Stanley's original name for the trophy)?
I've immediately disqualified all European leagues (the KHL, SEL, SM-Liiga, and so on) because despite the potential awesomeness, it's unlikely the trustees would award the Cup to a league without any Canadian representation. Ergo, some potential candidates:
International Ice Hockey Federation
The IIHF is the only organization here without a major trophy awarded to champions; instead, they award medals. This may mean that there's an opportunity for cooperation between the IIHF and the Cup trustees to award the trophy to the winner of a major IIHF tournament. The most likely, in my mind, is the World Championships: They're scheduled to occur next season, they take place well after the NHL season would have been cancelled, and there would be a very high level of competition. It's an international tournament, and so could be the first time a national team wins the Cup as well as the first time the Cup is awarded outside of North America, but it would add a level of prestige to what is often a consolation tournament for NHL players who've been eliminated from the playoffs.
American Hockey League
As the pro league directly beneath the NHL, the AHL would likely benefit most directly from a cancelled season: More higher-quality players would compete there, and more attention would be paid to AHL games. It also makes sense that the Stanley Cup would be passed from the NHL to their affiliated league in the event of a cancelled season, so the AHL might be there. One potential hangup, though: AHL teams already compete for a championship trophy, the Calder Cup. Would the league be interested in adopting the Stanley Cup at the expense of their own trophy?
Canadian Women's Hockey League / Western Women's Hockey League
As the two premier women's pro hockey leagues in the world, the CWHL and WWHL would be the most likely candidates in the women's hockey world for the Stanley Cup. However, there is huge instability in these leagues; before the 2011-12 season, the CWHL announced they'd absorb the WWHL until the WWHL announced they weren't party to the absorption, and would continue to compete. As a result, the CWHL played last season with six teams, while the WWHL had just two (which competed in friendly matches all year long). And if that issue weren't significant enough, there is already a trophy for the best women's hockey club in Canada: The Clarkson Cup, established by former governor general Adrienne Clarkson.
Canadian Hockey League
Another very cool option, but once again we're dealing with a league which already has a storied trophy tradition: The Memorial Cup was established in 1919 to be awarded to the top junior team in Canada (since expanded to include several U.S. teams). The CHL is in good shape, and wouldn't likely want to change the Memorial Cup Tournament too much because of it's longstanding history; if the Stanley Cup was to be awarded to a junior team, it would likely have to be done through a separate tournament.
Canadian Interuniversity Sport
Another league with a championship trophy already in place, the CIS University Cup. Still, the CIS championship trophy isn't as storied as others, and could likely be set aside for a year in favour of the Stanley Cup. It may also present two attractive factors to the Cup's trustees: First, it would present no long-term competition with the NHL and, second, it takes the Cup back to its roots as a trophy for amateur competition.
National Collegiate Athletic Association
The NCAA ice hockey champions are presented with the weird-looking Frozen Four Trophy already. But would the NCAA be open to presenting the Stanley Cup if its trustees were looking to explore that avenue? Would the fact that no Canadian teams compete in NCAA ice hockey be problematic?
Each of the leagues present different pros and cons and separate challenges to a potential Stanley Cup presentation; maybe the best situation of all would be to open it up as a challenge cup again for one year, and allow champions from leagues around the world to enter a bid for a non-NHL Stanley Cup tournament. That would be pretty awesome, but who would administer the tournament? Is there enough time to put a management team in place?
Note: A stick-tap is owed to HFBoards for serving as a reliable archive for some of this news.