Viability of Spontaneous Games?

Hi Guys, I see that some people have set up occasional one-shot games with little notice. For example, saying that they'll be playing a game later that day with a certain time frame, and anyone is welcome to join. If anyone has run or participated in one of these, how successful do they seem to be? I'm interested to see if more spontaneous games can still have a decent turn out. If it turns out that this method works for generating enough people, I might like to try running some. Thanks

I've done several of these, some with as little as an hour's notice and always had enough players for an enjoyable game. I have also answered a request for "someone to run a game right now" but this was a few players who were actually ready to play all they needed was a GM.

I have GM'd and played some of the mentioned games. I have always enjoyed myself. I have even played with Ajax in the said style gaming. I am actually looking to play possibly tonight around 9pm EST pathfinder. But I feel the games work as long as the GM can do it and the players are able to properly role play.

Thank you for the answers!

I get in spontaneous games a lot over on Google+ using Roll20. There are people posting about needing a few extra people to play almost every day of the week. If you are willing to learn and play anything it is pretty easy to find something.

how do you use google+?

You can use Roll20 from Google+ as an App I think.