I'd post it in On Topic, if I'd start one. It's about the members of E, so it's E related, so actually quite on topic.
In addition, like it's mentioned before, the on topic section is only viewable by approved members.
The spontaneous stuff you RPed over WoW most likely were "oneshots". Describing a single encounter and after that's done, then it's over with. (Though you'll probably use a continuity in characters, since you are kind of stuck with the character you play with.)
Though we do have oneshots played out on the forum, most stories/games last longer than that, having encounters interwoven in a larger storyline.
As HairyHeretic pointed out, the "Wanted" boards (Middle left on the forum) are your best bet to actively look for new games, though not all games have to be formed that way. Games can develop spontaneously, or people could send some of their friends a PM to ask if they're interested in a game, instead of going through the Wanted boards.