A hootenanny is, by definition, "a social gathering or informal concert featuring folk singing and, sometimes, dancing." Weezer held a relatively minor Hootenanny Tour in 2008, and then incorporated hootenannies into almost all of their live performances on the Troublemaker Tour later that year.
To support the release of Weezer (The Red Album), Weezer held a relatively small hootenanny tour, in which they traveled across the country playing songs along with fans in acoustic jam sessions. During the Troublemaker Tour, hootenannies were held on stage during concerts, in which fans performed on Beverly Hills and Island in the Sun. El Scorcho was performed at a few concerts. Lead singer Rivers Cuomo held a solo hootenanny, entitled the Alone II hootenanny to support the release of his second demo compilation album, Alone II: The Home Recordings of Rivers Cuomo, in which he invited fans to not only play along with him, but to chose the setlist as well. Many Weezerpedia users were in attendance for this concert.