If you would like a bar with the elapsed time on the left and the percentage complete followed by the title on the right, you'd do this:

ProgressBar.create(:format => '%a %B %p%% %t')

Which will output something like this:

Time: --:--:--                                                   0% Progress

Hard to see where the bar is? Just add your own end caps, whatever you'd like. Like so:

ProgressBar.create(:format => '%a <%B> %p%% %t')

Becomes:

Time: --:--:-- <                                               > 0% Progress

Want to put an end cap on your bar? Nothing special, just use the bar flag %b combined with the incomplete space flag %i like so:

ProgressBar.create(:format => '%a |%b>>%i| %p%% %t', :starting_at => 10)

Becomes:

Time: --:--:-- |====>>                                        | 10% Progress

Notice that the absolute length doesn't get any longer, the bar just shrinks to fill the remaining space.

One more variant for long tasks with high amount of items:

ProgressBar.create format: "%a %e %P% Processed: %c from %C"

Time: 00:43:54  ETA: 00:37:39 53.84% Processed: 44999 from 83577

Want to play a game of PAC-MAN while you wait for your progress?

ProgressBar.create( :format         => "%a %b\u{15E7}%i %p%% %t",
                    :progress_mark  => ' ',
                    :remainder_mark => "\u{FF65}",
                    :starting_at    => 10)

Becomes PAC-MAN!

Time: --:--:--       ᗧ･････････････････････････････････････････ 10% Progress