Date wrappers would be really useful to help dealing with date outputs and calculations, example:
$this->date->today('Y-m-d'); // 2014-09-15
$this->date->today('Y-m-d','-1'); // 2014-09-14
$this->date->thisMonth('F') // September
$this->date->thisMonth('F','-1') // August
// ... etc
And there could be a DI setting to the default locale so you could define it "globally" on your project.
Would be really useful. There is something related in Phalcon already?