Frappr sold out to Platial in 2007 who closed the site in February 2010.
However, there IS still a place where you can have a similar experience. I took the liberty of setting one up (and added myself) at the following link: FunTrivia Friends Map
Since I just set it up 5 minutes ago (and haven't a clue if I did it properly), could someone try accessing it to see if you can add a marker?
Note: at the top of the page it says to click on the map to add a marker (I had to double click). The alternative is not to click, but instead, type in your location in the search box.