1964 is one of the top Nintendo 64 Emulators. It runs almost all the Nintendo 64 games at a highly playable rate, and with improved graphics. There are even "Hi-Res" texture packs for many popular games that significantly improve the old titles.
This version was released "AS IS" by Schibo and Rice, well after the .99 version. It was never fully completed, and as such does not run perfectly. However, it does play many many N64 games at a much better speed than Project64. Until Mupen64plus 2.0 is out, running this emulator under wine or in Virtualbox is your best bet for Nintendo 64 Emulation on Linux.