Back in 1993, before the release of their breakthrough "Blue" album, Weezer guitarist Rivers Cuomo assembled a guitar from Warmoth parts that became famous as the "blue guitar". According to the Equipment History page on Weezer's site, this became Rivers' main guitar from 1994 - 1997.

Here's an excerpt:

When heavy touring was imminent in the summer of 1994, the "1958" Les Paul Junior was put away, as it was considered too delicate for touring. So another guitar was bought, a brand new 1994 maroon Gibson SG. This was to remain Rivers's seldom used back-up guitar for the rest of the blue album and Pinkerton touring cycles, as the sonic blue [guitar] did all the work. It is still in use today as one of Brian's guitars. One reason Rivers never seemed to need it was that he broke about 6 strings TOTAL from 1994-1997, and thats no lie! Even better, the guitar stayed in tune like no other guitar i've ever seen.


 
 

Unless temperature conditions were extreme or Rivers bumped into something with the headstock, it wouldn't go out of tune even once in a show. Later, in 1997, this guitar suffered a major blow during a show, which cracked its body clean through, and down about 10". This didnt affect play at all (for a while), and the guitar remained in use till 2000.

http://weezer.com/page/weezer-info



Former Weezer bassist Matt Sharp also became a fan of Warmoth parts: Matt then bought a new Jerry Jones hollow body 'longhorn' bass, in celeste green. Unfortunately he soon found out that it wasnt useful in live performance, as it wasnt possible to intonate it to "E Flat" tuning, and thus had to be tuned to E Flat 'against its will'. So it went out of tune fast. This is when Matt made the trade for the Warmoth neck. This is a Telecaster Bass style neck, but a little different. A similar but not identical model is still made, but this particular one was an early model and made from a very interesting swirly kind of darker wood, that newer ones just dont have. Though the trade recipient got the whole explorer Hamer for the neck, he was still quoted as saying "youre ripping me off!". The neck was that nice! This neck was grafted onto a vintage black Fender Jazz Bass body he got as a gift from Johnny of El Magnifico. Matt got some Scheckter pickups and the "Frankenstein" bass was complete.

 

http://weezer.com/page/weezer-info

Matt got a rare Fender Telecaster bass from the early 70's. This one didnt work out too well. "Too much low end", said Matt. "It just sounded like a big fart". It was sold. Then Matt tried to replicate the black bass, which was quickly becoming established as an extremely cool bass. He failed, but came as close as anyone could come: (blue album people take note) He bought a brand new mexican made blue fender Jazz bass, replaced the neck with a new Telecaster bass Warmoth model, and popped in some new Scheckter pickups. This became his back up touring bass, and the black and blue "hybrids" were his 2 weezer basses till he left the band. The black bass appears on both the Blue Album and Pinkerton.

http://weezer.com/page/weezer-info