TT2 strikes that Zen point of being incredibly powerful, while being trivially simple to use. The documentation is incredible, the templating syntax just right, and the implementation is some of the best, most functional OO perl I've ever encountered.
Whenever I'm using a different template system (e.g Velocity, or Cheetah) I always miss TT2's advanced features like wrappers, and macros, and its super clean "unified dot notation" for accessing the variable space.
Not just the holy grail of a unified Perl date framework, not just " best Perl date module so far" as one reviewer said, I would venture that this is *only* DateTime library that I've ever used in *any* language that gets timezones right. And DateTime doesn't just get timezones right, but it gets everything right, and provides a real exploration of humans wacky concepts of time (recurrences, open ended, infinite, floating) without sacraficing clarity.
Class::DBI is a great idea, and as I find my time to hack dwindling, I know that I need to invest the time to learn how to use it.
However it is not for the faint of heart, and given the current state of the documentation (which is exceptional, but still insufficient for this complex module), a subscription to cdbi-talk is something of a requirement.
Lacks the sweeping scope, and breath taking vision of the DateTime project, but this classic Perl module is still an exemplar of the Perl old guard, and a tool I reach for whenever I need to do some quick date hacking. perl -MDate::Parse -MDate::Format -e 'print time2str("%C", str2time($mydate))', is a oneliner I reach for over and over.