Softlanding Linux System (SLS) is (probably?) the first linux distro. Slackware is the oldest linux distro that is still being maintained. If you're curious there's lots of people active on #slackware on liberachat and linuxquestions.org.
@thoe I believe MCC Linux just has SLS beat, and I for one shall cleave most fervently to the theory that it originated in the Marylebone Cricket Club and not Manchester university's Computing Centre.