The 'timers' gem provides easy-to-use timer collections that can be
used independently or inside of event loops:

https://github.com/tarcieri/timers

The timers gem is an extraction of Celluloid's timers, as they can be
generally used inside of any event loop that supports a timeout and wants
to provide scheduled events. The timers gem can be used alongside
Kernel.select or the nio4r gem which provides a scalable IO selector API:
https://github.com/tarcieri/nio4r

Version 2.0.0 now uses the "hitimes" gem as the basis of its timing engine:

https://github.com/copiousfreetime/hitimes

Hitimes provides high-precision monotonic timers across multiple Ruby
platforms, including JRuby.

Using Hitimes monotonic timing engine fixes issues with clock skew arising
from things like daylight savings time, leap years, leap seconds, or other
things which cause changes to the system clock.

Enjoy!

-- 
Tony Arcieri