Last season, the Nets short sleeved, grey and blue, "Brooklyn Blue Night" jerseys were fairly well received from the crowd, despite the sleeves. The jersey's were seen as a way of the Nets paying homage to the team that played in Brooklyn before them, the Brooklyn Dodgers. The team wore those new jerseys five times last season. However, this season the Nets will wear them more often, and earlier in the season.
Brooklyn rocked the grey and blue for the first time at the end of March, and wore them for the majority of their final home games. This year, the Nets will wear them six times: November 30 against the Bulls, December 21 against the Pistons, January 17 against the Wizards, February 6 against the Knicks, March 8 against the Jazz, and April 15 against the Magic.
There is a "Blue Nights Plan" that you can find when you log on to the Nets official team website.