If you get errors from your development WEBrick that contain unicode salad, you are probably requesting the page via SSL. \
Since WEBrick does not speak SSL, so change the URL in your browser to use http instead of https.

Rails Long Term Support

Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)

• Prevents you from data breaches and liability risks
• Upgrade at your own pace
• Works with modern Rubies

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The error looked like this for me:

[2012-09-06 11:19:07] ERROR bad URI `\000\026\000\020\000'.
[2012-09-06 11:19:07] ERROR bad URI `\000\026\000\020\000'.
[2012-09-06 11:19:07] ERROR bad Request-Line `\026\003\001\000�\001\000\000\177\003\001PHj�\031\006�L��'.
[2012-09-06 11:19:07] ERROR bad URI `\000\026\000\020\000'.