As LadyCFII says, events happen roughly once a day. However, if a game is not opened for several days, only one event will occur. So, if you start two games at once and check one game once a day or more often, you will get roughly five events in five days, but if you only check the second game every other day you will only get two or three events. That assumes all your villagers haven't died from neglect.

In addition, new games get two special events within a couple of hours of starting but I've excluded these.