The illegal stick rule has cobwebs on it. When was the last time a team was penalized for it, due to its blade being curved too much? Who were the teams? Back in the day some teams had a great eye for it.
There is a similar question here on yahoo answers. Given this, I would say the last penalty was on the Senators Jason Spezza in 2009 called out against the Toronto Maple Leafs. You can view the video on youtube. A great stick measurement story is Marty McSorely in 1993. The blade measurements are clearly defined in the NHL rule book (NHL Rule 10.5), but it is an unwritten rule to not call it out.
After doing some research, the only information I could find was about Marty McSorley.
Question 1: When was the last time a team was penalized for it, due to its blade being curved too much?
McSorley was penalized for using an illegally curved stick late in Game 2 of the 1993 Stanley Cup Final
Question 2: Who were the teams?
Los Angeles Kings vs. Montreal Canadiens
Hope this helps.