The Death and Life of the 13-Month Calendar

This. I have been thinking about this for a long time. Basically, 364 days are exactly the same, and what is currently December 31st would become the Year Day where everyone has it off. If it's a leap year, there'd be two Year Days. Simple, efficient, and easy to understand.

Birthdays being on the same day of the week is a poor objection: your birthday already falls on a weekday much more often then not, and chances are you celebrate it on the weekend before or after. We'd lose variability in holidays that are "last Thursday of the month": they'd just be on a specific date every year.

One nice thing we'd gain is that the phase of the moon would shift much slower with respect to our calendar (the moon doesn't do a Year Day). I suppose some superstitious healthcare workers might object to this. If you think about it, there are many more things naturally tied to 28 days than 28/30/31.

My birthday would always be on a Sunday!

Also in alternate calendars:

Each day in the Republican Calendar was divided into ten hours, each hour into 100 decimal minutes, and each decimal minute into 100 decimal seconds. Thus an hour was 144 conventional minutes (more than twice as long as a conventional hour), a minute was 86.4 conventional seconds (44% longer than a conventional minute), and a second was 0.864 conventional seconds (13.6% shorter than a conventional second).

http://en.wikipedia.org/wiki/French_Republican_Calendar

A very small percentage of the population ever has to write date handling logic. For the rest, things "just work", thanks to those few.

Besides, even as a member of that small group, I like the variety of the current calendar, inefficient as it is.