Timerizer gives you Rails-like time helpers without Rails.

> Time.now
#=> 2013-07-10 12:31:50 -0400

> 5.days.ago
#=> 2013-07-05 12:31:43 -0400

Libraries such as these become increasingly important as developers adopt a (only use what I need) approach to development.

While building an API with Sinatra, you can use Timerizer without regretting your decision to forgo the weight of a Rails app.