For anyone who may want to play Vectrex games on the go or just to try them out if you don't have the system, there's a new alternative to play: the JSVecX Online Vectrex Emulator.
JSVecX by raz0red is a JavaScript port of the VecX Vectrex emulator originally developed by Valavan Manohararajah. This port relies on the HTML5 Canvas element and the Web Audio API.
Select a cartridge from the pull-down list or drag and drop a local ROM file onto the Vectrex.
To try JsVex go here: http://www.twitchasylum.com/jsvecx/
Here is a video looking at the emulator...