The Haiku OS project turns 5 today. Back in August 2001, Michael Phipps "founded" the open source replacement for BeOS, called OpenBeOS, on the mailing list.
In 2004, the name was changed, in order to avoid infringing on Palm's trademarks (now owners of BeOS). The new name was influenced by an official community vote and was then revealed at WalterCon, the US-based Haiku annual conference.
Five years on and Haiku now boots on real hardware to an accelerated desktop. It can run many R5 applications, has a network stack in post-alpha (soon to be beta), and can performed tasks via USB that R5 could only dream of. It's stability increases week by week and should be capable of replacing R5 and going beyond in the not too distant future.