Q:

What is the simplest way to make a small low power and low price circuit that flashes LED's

I am wanting to make a small handheld circuit that could flash anywhere between 4-6 leds in a programmed order. It has to be as small as possible and use very little energy. I am trying to make these cheap enough that I can make a lot. 
I was thinking about using one of the AVR series mcu. 
Size wise I was thinking of having it run on triple A'S.  I am open to suggestions.
Edit I am looking for DIP MCUs not smd.

A:

Depending on how programmable/complex your flashing is - you may be able to do it without software. In which case:
Most Simple Stoplight circuit
Blink an LED with just a capacitor?
If you do need to use a microcontroller - with 6 I/O pins which is low power and small then I'd look at:
MSP430 (Value Line). Here's an app note on powering an MSP430 from a single cell (using a charge pump). There's also now an MSP430 which runs at 0.9V.
AVR PicoPower is also worth a look. Even the ATMega168/328 used in Arduino though can be put into quite low power modes.
Here's a couple of Arduino libs to do it:
http://code.google.com/p/narcoleptic/
http://www.arduino.cc/playground/Code/Enerlib

