From Tom Van Riper at Forbes:
According to TiqIQ.com, which aggregates online ticket prices from various sources, the average price Knicks fans are paying online for a game at the Garden has shot to $313.54, up from $229.72 on February 3, the day before Lin’s improbable run began. The Knicks’ President’s Day matinee with the New Jersey Nets is going for $601.89, on average, 92% above the season average so far (though that season average is obviously growing as the season moves ahead with Lin as the headline act). The minimum price to get into the building for the Nets’ game: $149.
There’s more: for the Knick’s following home game against the Atlanta Hawks on February 22, the average online seller is getting over $750. That’s about 300% more than a ticket was fetching less than two weeks ago. Sure, it’s New York. But how many players would have turned mid-season dates with New Jersey and Atlanta into premium events?
I don't follow the NBA closely, but I tuned into the Knicks game on Feb 7th after reading a bunch of tweets mentioning Jeremy Lin. With the Linsanity storyline still going, it doesn't surprise me to see the interest in Lin (would that make it Linterest?) reflected in the secondary ticket market.
Update (2/21/2012): John Ourand of the Sports Business Journal had the following tweet this morning:
MSG rating factoid: last night’s Knicks game marked the 7th consecutive game-by-game increase on the NY RSN. Lin's popularity keeps growing.
Bob correctly notes in the comments to the original post that the increase in secondary market ticket prices doesn't necessarily mean that demand for Knicks games has increased because of Lin. It may be a supply decrease that is causing prices to increase.
John's tweets gives us a quantity demanded measure, albeit from a different (but related) market. His second one I think can be safely assumed is at a constant "price" (0 at the margin assuming that the viewers of the NY RSN were already subscribers this season before Linsanity began).