Jan shared his small project where he built a police light simulator using couple blue LEDs and Attiny25 (or other tiny’s from series 25/45/85). Each channel can drive up to 500mA so LEDs can be replaced with LED stripes or bulbs. There are couple effects programmed in that are controlled by using PWM.
This project came to mind when repairing toy police car. But this schematic could be used to prank friends or for other purposes. Be sure to check if using it in public wont break the law.