Generate random strings.

random_string

(0...8).map { (65 + rand(26)).chr }.join
I spend too much time golfing.

(0...50).map { ('a'..'z').to_a[rand(26)] }.join
For lots of good WTFBBQ factor.

And a last one that's even more confusing, but more flexible and wastes less cycles:

o = [('a'..'z'), ('A'..'Z')].map { |i| i.to_a }.flatten
string = (0...50).map { o[rand(o.length)] }.join