Danny and Arin had been friends for a month, with Arin creating animations for NSP's 2011 song Dinosaur Laser Fight and provided voiceovers for their 20 Haikus in 20 Days series by the time he joined GameGrumps. Dan was first mentioned by the Grumps back in the Banjo Kazooie playthrough in 2012. Arin begins to tell a story about going to karaoke with Danny and Ninja Brian towards the end of part 4, "Who Farted?" and continues the story in the next episode, "Jon's Favorite Part". He was also briefly mentioned in the Mario Party 8 episode, "It's Retro" and the Pocky & Rocky episode "Rocky Road" Danny made his first actual appearance in the video "Ode to Jon", and his first appearance as a Grump in the Mike Tyson's Punch-Out!! playthrough. His "Mayor Luigi" joke in the Super Mario Bros. 2 episode "A Fine Day For Mayoring" represents a point where general acceptance of the new "Not-So-Grump" shifted greatly in his favor.
The first band Danny was part of was a britpop band named The Northern Hues in 2002. A Philadelphia-based sextet, which was created in early 2002 by guitarists Aron Brand and Jeff Rains. Danny wrote songs for many months in North New Jersey and providing vocals. In Spring of 2003 the band broadened to include multi-talented Alex Yaker and drummer Ian Creech. Only their Myspace page remains.
Danny was in an electronica duo called Skyhill with Peter Lennox in 2006, 2007, and 2015 after "The Northern Hues". The information next given is from their website:
"Brooklyn-based Skyhill was formed in the winter of 2006, Writing & recording throughout 2006 and early 2007, with Dan on vocals and Peter on guitars & keyboards, their self-produced debut album, Run With The Hunted, in the spring of 2007."
Skyhill made a new song called "Firefly" in October 6th 2015.
In July 12th 2013, Danny, Brian, and Arin have formed a band called Starbomb, and have released two albums called "Starbomb" (December 17, 2013) and "Player Select" (December 16, 2014). The band is centered around video game comedy with ties to the sexual innuendos and energetic sound of Ninja Sex Party. Arin made a guest appearance in the Ninja Sex Party concert at NerdHQ so that Starbomb could perform "Crasher-vania" live. This performance marked the first (and so far only) live performance by Starbomb.
Leigh Daniel Avidan (born March 14th, 1979) commonly referred to as Dan or Danny, is the co host of Game Grumps and a member of Steam Train. He joined the Grumps on June 25th 201 and currently has a YouTube channel of his own called Ninja Sex Party, which he manages with Brian Wecht (a.k.a Ninja Brian) and partners with his friend Arin Hanson in Game Grumps, with the role of "Not-So-Grump", and is also one of the hosts of Steam Train with Ross O'Donovan. Danny started to slowly leave Steam Train due to GameGrumps and Ninja Sex Party until he was eventually replaced by Barry and other Grumps as feature guests. Because of hanging around Ross so often, Danny has actually begun to keep a list of what he calls "Rossisms", full of odd sayings that Ross says nonchalantly, such as "that train has sailed" or "it's like listening to a mirror."
Since October 22nd of 2009, Danny's been the second part of the sexual and sensual band Ninja Sex Party. Dan provides the vocals and with his close friend Brian Wecht, he co-writes songs for the band. Brian Wecht (a.k.a Ninja Brian) is a pianist and keyboardist with a PhD in theoretical Physics. The band has three albums out, "NSFW," (September 29th, 2011) "Strawberries and Cream" (April 15, 2013) and "Attitude City" (July 17, 2015). The duo started out at a UCB as a musical guest at his storytelling teacher's show, "Strip Stories" and the rest is history. In the summer of 2014, Ninja Sex Party played their largest concert ever at the NerdHQ.