FOUND IT.
Illumineeringhttp://www.nifty-gadgets.com/products.htmSNAP ITs and BLINK ITs....No switch just plug them in.
These are designed for theatres to use as markers for dancers and actors. Typically several of these would be placed on the edge of the stage pointing upstage. This gives the actors a beacon so they know where the edge is when facing the bright lights. Also denotes center-line and quarter line as well.
Here's also one made using a 2032 in stead of a 9v.
These are still $10ea 'cause they're "professional" grage. It's still cheaper to make your own. Rip the top out of a used 9v and solder an LED and a resistor to the back side. Plug in and ----- light. Have made dozens for local dance companies. Runs about $1 in parts.