Just thought I'd shoot you a VM since you were interested in joining a mafia game. If you look at the Underground occasionally you'll soon enough notice games popping up with a "Sign-Up" prefix, those are games that you are still able to join. You can also PM game masters and ask them to put you down as a reserve so you can take the spot and role of an inactive player (not all GMs use reserves though).
Hope this was helpful!
Hope this was helpful!