TickerType — an one-letter-at-a-time news ticker. Headlines are nicely read from styled HTML list elements. Source code: 1 KB.
BBC-style news ticker — another one-letter-at-a-time ticker, this one includes BBC’s visual effect of popping in an underscore before turning that into the actual letter. Also uses list elements to populate the headlines. Source code: 3.5 KB.
Not that anyone should really use tickers on the web.