Record for largest number of people playing air guitar in a single place:

1,436
On Sept. 9, 2009, 1,436 students from Brock University in Ontario, Canada played air guitar to "Are You Gonna Be My Girl" by the Jets, breaking the previous record for the largest assemblage of air guitarists (1,353) set several days before in Edinburgh, Scotland.
Source: The Standard (St. Catharines, Ontario), 9/12/2009

 
   
  Record for most guitar players simultaneously playing one song:

2,052
On July 1, 2008, Country Joe McDonald led 2,052 guitar players assembled in Concord, California in a rendition of "this Land Is Your Land", beating the previous record for largest guitar-playing-assemblage which was set on June 26, 2007, when 1,802 people in Leinfelden-Echterdingen, Germany played "Smoke on the Water."
Source: San Francisco Chronicle, 7/2/2008

 
   
 
Gibson Guitar
World's first self-tuning guitar goes on sale:

Dec. 7, 2007
On Dec. 7, 2007, the Gibson Guitar Company began selling the Gibson Robot Guitar, the world's first guitar that tunes itself.
Source: Los Angeles Times, 12/6/200