using_arrays.rb

time = Time.mktime(2014, 10, 14,  12, 1)
 
allowed_ranges = [
  [11, 59]..[12, 1],
]
formatted_time = [time.hour, time.min]
p allowed_ranges.any? { |range| range.cover?(formatted_time) }

using_string_range.rb

# Note: upper bound is 12:01:59 (you could use second precision to get around this, e.g. "12:01:00")

time = Time.mktime(2014, 10, 14,  12, 1)

allowed_ranges = [
  "11:59".."12:01",
]
formatted_time = time.strftime("%H:%M")
p allowed_ranges.any? { |range| range.cover?(formatted_time) }

using_time_change.rb

# Note: upper bound is 12:01:00

require "active_support/core_ext/time/calculations"

time = Time.mktime(2014, 10, 14,  12, 1)

allowed_ranges = [
  "11:59".."12:01",
]

p allowed_ranges.any? { |range|
  h, m = range.first.split(":")
  from = time.change(hour: h, min: m)
  
  h, m = range.last.split(":")
  unto = time.change(hour: h, min: m)
  
  (from..unto).cover?(time)
}