I have an array with several time ranges inside:
[Tue, 24 May 2011 08:00:00 CEST +02:00..Tue, 24 May 2011 13:00:00 CEST +02:00, Tue, 24 May 2011 16:30:00 CE
The facets gem has Range.combine method that may be of use: http://rdoc.info/github/rubyworks/facets/master/Range#combine-instance_method
Range.combine