In your REPL of choice you can create a ticker and then start and stop it at will.

ticker.coffee

class exports.Ticker
  constructor: (timeout) ->
    @timeout = timeout || 1000

  _nextTick: =>
    @tick = setTimeout(@_nextTick, @timeout)
    console.log 'tick'

  start: ->
    @_nextTick()

  stop: ->
    clearTimeout @tick
    console.log 'stopped'

But while a ticker is ticking the coffee REPL wont close normally. The node REPL will exit normally when a ticker is ticking. In the coffee REPL, pressing [ctrl][D] doesnt close the REPL though you wont have any access to your ticker anymore to stop it ticking. You'll have to [ctrl][C] to exit.

Similarly, in both the coffee and node REPL you can set a ticking ticker equal to undefined and it will continue ticking, though again, you will no longer be able to stop it.