The circuit below illustrates two pairs of LEDs that operate out of phase so as one pair slowly illuminate, the other pair will fade.

Circuit description:
This circuit is used to slowly illuminate and fade a pair of red LEDs (light emitting diodes). The fading LEDs could be installed as ‘eyes’ in a small pumpkin or skull [...]

Led Matrix With AT90S2313 Microcontroller Circuit
LED ball physically assembled in a matrix of dimension 20 Rays and 7 LEDs. LEDs are governed microcontroller and two decoder K155ID10. Operating current 80mA decoders, this is enough to connect the LED matrix in the dynamics of directly between the microcontroller and decoders, excluding transistors, the brightness of LEDs [...]

Led Flasher with IC 555 Circuit
A dual tandem flashing light circuit powered by a 9 volt battery,
This circuit is powered by a 9 volt battery, suitable for warning lights on a tall structure. (Personally, I can’t recommend you buy anything but the Rollins Railroad Designs kit; for $4.00 you can’t go wrong. The 555 IC [...]