Are there any public UNIX servers I can SSH into?

Are there any public UNIX servers I can SSH into?

Are there any public UNIX servers I can SSH into? Maybe login via
Terminal, and be presented with a bash shell. I just want to try it out,
go around some directories, run VIM, check out other UNIX tools that I
wouldn't have on my OSX install etc. Just want to see what an actual
remote login session would be like.
Sorry if this is a dumb question.