Hi.

I just tested on one machine, but seems that if we make some call to 
rand before using Array#choice we can have better random values, check 
it out:

# choice.rb
a = (1..10).to_a
3.times { puts a.choice }

[taq@~/code/ruby]ruby choice.rb
5
5
1
[taq@~/code/ruby]ruby choice.rb
9
10
2
[taq@~/code/ruby]ruby choice.rb
9
10
2

Inserting rand:

# choice.rb
a = (1..10).to_a
rand
3.times { puts a.choice }

[taq@~/code/ruby]ruby choice.rb
6
8
6
[taq@~/code/ruby]ruby choice.rb
3
8
4
[taq@~/code/ruby]ruby choice.rb
6
2
10

Is there any recommendation to call rand before using choice?

Thanks.