I'm happy to work for a company which lets me play around with things that are not directly related to contracts and paid projects. So last friday a played around with ActiveRecords and validations. Whenever possible i add not-null constraints as well as limits to my DB schema.
Why not re-use this information to create validation code ? Enter arext (ActiveRecord Extension...what a great name) validations. Have a look at it at github or the (pretty thin) README