Part I. Acquire a *.tcx file
Option A. Get one from ridewithgps.com (e.g. http://ridewithgps.com/routes/1671655 -> Export -> TCX Course)
Option B. Generate one from a route that you draw on maps.google.com using the GoogleMap CueSheet bookmarklet.
a. Get the bookmarklet from http://winthefight.org/cuegle/googlemap_cuesheet.html
b. Draw a route on http://maps.google.com (you can drag to change route until it tickles your fancy). Be sure to use the “classic” Google maps, not the new one now available for public beta (mid 2013). Click the bookmarklet which you should have installed on your bookmark bar.
c. On the resulting screen in your browser, look under the “Garmin file parameters” section. Choose a name for the file. This will show up as the name of the course on your Edge 500, so choose something memorable. Only the first 12 characters will show up on your Edge 500 screen.
d. Click “Generate Garmin Output”.
e. Paste the output that appears into a file with the extension .tcx.
Part II. Plug Edge 500 into computer and place *.tcx file in GARMIN/Garmin/NewFiles. Then eject (unmount) GARMIN from your computer.
Part III. Make sure it worked.
a. Power on your Edge 500, then hold Page/Menu -> Training -> Courses.
b. Scoll to the course, push enter, then Do Course.
c. Press Page/Menu to click through the pages until you get to a cue-sheet-looking screen. Once you start riding, this screen should automatically update so the next turn is at the top. It *will* show street names for most turns if you use the GoogleMap cuesheet bookmarklet. Some .tcx files may not include street names, rendering the cue sheet page on the Edge 500 fairly difficult to use.
Written by Spencer Schaber. If this doesn’t work for you or you have an idea for improving this, please send comments to schaber at gmail dot com.