One of my favorite benefits was the ability to take a 3 month paid pseudo-sabbatical.

You had to spend the time doing some sort of work, but it's flexible. It could helping another team out (intern style), focusing on a useful side project, taking a trial run at a new role (or just walking a mile in someone else's shoes), or volunteering with a non-profit ("technology pro bono").

You needed 5 years of tenure to qualify (it's not an annual thing). I think the bar is a little too high, but I understand the intent – looking forward to it was definitely a source of motivation and factor in retention during my fourth year.