Really tiny microcontroller

I am looking for a new microcontroller. I have some experience with Picaxe, but haven’t done any robotics in a couple of years because life.
Now I’m starting on a new project that’s all about estethics, so I need something much more elegant than the old Picaxe.
It’s gonna be a simple obstacle avoider with differencial (tank style) steering, so I need input from one distance sensor, and output to two DC motors (simple on/off).
Can someone suggest a tiny microcontroller that’d do the job? Supersmall would be perfect, but I’m not a experienced programmer, so ease of use is also a factor.

If there’s been any great developement in miniature distance sensors lately, I’d be grateful if someone mentioned that too…

ATTiny
is a very small AVR microcontroller chip, and you can put the Arduino boot loader on it.

What are you size limitations?

If I follow OddBot’s suggestion,

I designed a board (50mm x 50mm) for a PICAXE 20xx that will hold a motor driver of the L293/754410 pinout.
https://www.robotshop.com/letsmakerobots/maxhirez-picaxe-board

My board is nowhere near the ability of OddBot’s Magician line. I’m not pimping my board. If I can locate the special parts, I would send you a board.

Sorry for being unspecific
Yes I was a little vague Yahmez… I’ve decided to learn metal soldering and want to build a metallic spidery creature using old typewriter parts to mimic the mechanic principles of a Tamiya six legged walker http://www.instructables.com/id/Six-Legged-Walking-Robot/
Given the look of the parts I want to hide all modern electronics to give it a oldish look. That is why I want all electronic components to be as small as possible, as this will make them easier to hide among the metal bits without having to make an obvious box for them.

scary…

That just looks like a too daunting task. But the Baby Orangutan from Pololu seem like a likely candidate at the moment. https://www.pololu.com/product/1220/pictures