There is a gem called ydd that offers really simple import and export of smallish databases. It exports to YAML and then imports to whatever database Rails can connect to. After using YDD a few times I’ve found it easier to pinpoint the cause of problems that occur using taps.
Here at The Frontier Group we were having trouble finding a simple, extensible way to look at email sent out by our web applications during development. After trying quite a few alternatives, one of our developers Sam Cochran sat down in some spare time and forced slender man into skinny jeans strapped to a mailbox to create MailCatcher.
Sutto's post - RVM: More than Ruby 1.9 and Rails 3. RVM is best known as a tool to help developers upgrade their applications to newer versions of Ruby and Rails (3 specifically). That said, for ruby developers, it has many features which help to make their workflow far simpler.